M25 Junction 23 to 27 - Section 5 Managed Motorways – All Lanes Running Stage 3 - Preliminary Design
Environmental Assessment Report
Document No: 5084755-S5-DO-EN-251
November 2012
Volume 1
M25 Junction 23 to 27 - Section 5 Revision: E Environmental Assessment Report Volume: 1
Contents Section Page 1. Introduction 8 1.1 Project Identification 8 1.2 Purpose of this Report 8 1.3 Scope and Content 9 1.4 The Overseeing Organisation 10 1.5 The DBFO Contractor 10 2. The Project 11 2.1 Background to the Project 11 2.2 History of the Project 11 2.3 Regulatory Framework 12 2.4 Project Objectives 12 2.5 Any Further Support of Government Policies 14 2.6 Project Description 14 2.7 Land Use Setting and Land Take 15 2.8 Construction, Operation and Long Term Management 15 3. Alternatives Considered 18 3.1 Design Options 18 4. Environmental Impact Assessment Methodology 20 4.1 Scoping 20 4.2 Surveys and Predictive Techniques, Method and Constraints 21 4.3 Changes to DMRB 22 4.4 Significance Criteria 22 4.5 Mitigation and Enhancement 22 5. Air Quality 23 5.1 Introduction 23 5.2 Study Area 23 5.3 Baseline Conditions 24 5.4 Methodology 38 5.5 Regulatory/Policy Framework 49 5.6 Design, Mitigation and Enhancement Measures 58 5.7 Magnitude of Impacts (Change) 59 5.8 Supplementary Information 73 5.9 Indication of Any Difficulties Encountered 73 5.10 Summary 73 6. Cultural Heritage 75 6.1 Study Area 75 6.2 Baseline Conditions 75 6.3 Methodology 75 6.4 Value (Sensitivity of Resource) 76 6.5 Regulatory/Policy Framework 76 6.6 Design, Mitigation and Enhancement Measures 81
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6.7 Magnitude of Impacts (Change) and Significant Effects 81 6.8 Significance of Effects on Plans and Policies 92 6.9 Indication of Any Difficulties Encountered 92 6.10 Recommendations 92 6.11 Summary 92 7. Landscape 93 7.1 Study Area 93 7.2 Baseline Conditions 93 7.3 Methodology 99 7.4 Value (Sensitivity) of Resource 104 7.5 Regulatory/Policy Framework 106 7.6 Design, Mitigation and Enhancement Measures 111 7.7 Magnitude of Impacts (Change) 113 7.8 Significant Effects 116 7.9 Indication of Any Difficulties Encountered 118 7.10 Summary 118 8. Nature Conservation 119 8.1 Study Area 119 8.2 Methodology 119 8.3 Baseline Conditions 120 8.4 Value (Sensitivity) of Resource 130 8.5 Regulatory/Policy Framework 132 8.6 Design, Mitigation and Enhancement Measures 138 8.7 Magnitude of Impacts (Change) 149 8.8 Significant Effects 170 8.9 Indication of Any Difficulties Encountered 170 8.10 Summary 170 9. Geology and Soils 171 9.1 Emerging Guidance 171 9.2 Study Area 171 9.3 Baseline Conditions 171 9.4 Methodology 173 9.5 Value (Sensitivity) of Resource 176 9.6 Regulatory/Policy Framework 176 9.7 Design, Mitigation and Enhancement Measures 178 9.8 Magnitude of Impacts (Change) 180 9.9 Significant Effects 181 9.10 Indication of Any Difficulties Encountered 184 9.11 Summary 184 10. Materials 185 10.1 Guidance and Introduction 185 10.2 Study Area and Baseline Conditions 187 10.3 Assessment 187 10.4 Indication of Any Difficulties Encountered 191 10.5 Summary 191 11. Noise 193 11.1 Study Area 193
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11.2 Baseline Conditions 193 11.3 Methodology 193 11.4 Value (sensitivity) of Resource 195 11.5 Regulatory/Policy Framework 196 11.6 Design, Mitigation and Enhancement Measures 199 11.7 Magnitude of Impacts 200 11.8 Significant Effects 204 11.9 Identification of Difficulties 204 11.10 Summary 204 12. Effects on All Travellers 205 12.1 Introduction 205 12.2 Study Area 205 12.3 Baseline Conditions 205 12.4 Methodology 208 12.5 Value (Sensitivity) of Resource 211 12.6 Regulatory/Policy Framework 211 12.7 Design, Mitigation and Enhancement Measures 213 12.8 Magnitude of Impacts (Change) 213 12.9 Significant Effects 216 12.10 Indication of Any Difficulties Encountered 217 12.11 Summary 217 13. Community and Private Assets 218 13.1 Guidance 218 13.2 Study Area 218 13.3 Methodology 218 13.4 Assessment of Effects 221 13.5 Indication of Any Difficulties Encountered 230 13.6 Summary 230 14. Road Drainage and the Water Environment 231 14.1 Study Area 231 14.2 Baseline Conditions 231 14.3 Methodology 235 14.4 Value (Sensitivity) of Resource 239 14.5 Regulatory and policy framework 241 14.6 Design, Mitigation and Enhancement Measures 244 14.7 Magnitude of Impacts (Change) 246 14.8 Significant Effects 253 14.9 Indication of Any Difficulties Encountered 261 14.10 Summary 261 15. Assessment of Cumulative Effects 263 15.1 Introduction 263 15.2 Baseline Conditions 263 15.3 Methodology 263 15.4 Cumulative Effects of the Project (Type 1) 264 15.5 Cumulative Effects of Multiple Projects (Type 2) 265 15.6 Summary 265 16. Conclusions 268
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16.1 Summary of Significant Effects 268 16.2 Summary of Mitigation Measures 270 17. References 274 18. Glossary 287
List of Tables Table 2.1 - Annual Average Daily Traffic 11 Table 4.1 - Study Area and Level of Assessment by Topic (as defined by DMRB) 20 Table 5.1: Relevant local air quality criteria (human health) 25 Table 5.2: AQMA within 200 m of the ARN 25 Table 5.3: Arlington Crescent continuous analyser (BBCMS) statistics 29
Table 5.4: Annual mean NO2 concentrations (µg/m³) at diffusion tubes within 200 m of the ARN (after bias adjustment) 30 Table 5.5 Critical Level for annual mean NOx for the protection of vegetation and ecosystems 37
Table 5.6: Estimates of site average background NO2 for determination of incremental dry N deposition rates in 2008 and 2015 37 Table 5.7: Critical Loads for N deposition at designated sites within 200 metres of the ARN 38 3 Table 5.8: Comparison of modelled and monitored PM10 concentrations (µg/m ) 45
Table 5.9: Approach to evaluating the significance of air quality effects (opening year, annual average NO2)47
Table 5.10: NO2 concentrations and changes with the scheme 59
Table 5.11: PM10 concentrations and changes with the scheme 62
Table 5.12: Summary Results – Evaluating Significance (6 questions on annual average NO2) 64
Table 5.13: EU Criteria for Evaluating Significance – M25 Section 5 Local Air Quality (annual average NO2)65 Table 5.14: EU Criteria for Evaluating Significance – M25 Section 5 Designated Ecological Sites (annual average NOx) 68 Table 5.15: Regional Emissions 71 Table 7.1 - Landscape Sensitivity and Typical Examples 99 Table 8.1 - Ecology Appendices and Document References 119 Table 8.2 - Summary of Construction Impacts, Mitigation and Significance 161 Table 8.3 - Summary of Operational Phase Impacts, Mitigation and Significance 166 Table 9.1 - Geology Across the Project 171 Table 9.2 - Geological and Soil Features within Study Area 172 Table 9.3 - Value of Geological and Soil Attributes 174 Table 9.4 - Definition of Magnitude of Impact 174 Table 9.5 - Definition of Significance of Effect 175 Table 9.6 - Definition of Significance of Effect 175 Table 9.7 - Value of Geological and Soil Attributes within the Study Area 176 Table 9.8 - Predicted Magnitude of Impacts during Construction Phase 180 Table 9.9 - Predicted Magnitude of Impacts during the Operational Phase 181 Table 9.10 - Significance of Effects during Construction 182 Table 9.11 - Significance of Effects during Operation 183 Table 100.1 - Estimation of the Level of Risk by Comparison of Consequence and Probability 189 Table 100.2 - Conceptual Site Model 190 Table 11.1 - Descriptors for Magnitude of Noise Impacts in Short Term 195 Table 11.2 - Descriptors for Magnitude of Noise Impacts in Long Term 195 Table 11.3 - Scheme Effects in the Detailed Calculation Area on Scheme Opening (2015) (Short-Term Impacts) 201 Table 11.4 - Scheme Effects in the Detailed Calculation Area by the Design Year (2030) 202 Table 11.5 – Do-Minimum Effects in the Detailed Calculation Area by the Design Year (2030) 203 Table 12.1 - Base Year 2004 Traffic Data 206
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Table 12.2 - Traveller Care Facilities 207 Table 12.3 - Travellers‟ Views – Magnitude of Impact 209 Table 12.4 - Significance Descriptors 209 Table 12.5 - Driver Stress/Frustration Magnitude of Impact 210 Table 12.6 - 2030 Do Minimum Traffic Data 215 Table 12.7 - 2030 Do Something Traffic Data 215 Table 12.8 - Significance of Effects 216 Table 13.1 - Planning Assessment Criteria 219 Table 13.2 - National and Regional Planning Policy 222 Table 14.1 - Watercourses in the Study Area 231 Table 14.2 - Target and Current Status of WFD Designated Stretches of Watercourses in the Study Area 232 Table 14.3 - Summary of the Water Environment Importance Assessment Criteria 236 Table 14.4 - Magnitude of Construction Impacts – Surface Water 237 Table 14.5 - Magnitude of Construction Impacts – Groundwater 237 Table 14.6 - Magnitude of Construction Impacts – Floodplain 238 Table 14.7 - Summary of Significance of Effect Criteria 239 Table 14.8 - Importance of Watercourses in the Study Area 240 Table 14.9 - Importance of Groundwater Attributes in the Study Area 241 Table 14.10 - Magnitude of Construction Impact on Surface Water – ERAs, Clockwise Carriageway 246 Table 14.11 - Magnitude of Construction Impact on Surface Water – ERAs, Anti-clockwise Carriageway 247 Table 14.12 - Magnitude of Construction Impact on Surface Water - Slip Road Widening, Clockwise Carriageway 247 Table 14.13 - Magnitude of Construction Impact on Surface Water - Slip Road Widening, Anti-clockwise Carriageway 248 Table 14.14 - Magnitude of Construction Impact on Groundwater – ERAs, Clockwise Carriageway 248 Table 14.15 - Magnitude of Construction Impact on Groundwater – ERAs, Anti-clockwise Carriageway 249 Table 14.16 - Magnitude of Construction Impacts of Groundwater – Slip Road Widening, Clockwise Carriageway 250 Table 14.17 - Magnitude of Construction Impacts on Groundwater - Slip Road Widening, Anti-clockwise Carriageway 250 Table 14.18 - Magnitude of Construction Impacts on Floodplain – ERAs, Clockwise Carriageway 250 Table 14.19 - Magnitude of Construction Impacts on Floodplain – ERAs, Anti-clockwise Carriageway 251 Table 14.20 - Magnitude of Construction Impacts - Slip Road Widening, Clockwise Carriageway 252 Table 14.21 - Magnitude of Construction Impacts - Slip Road Widening, Anti-clockwise Carriageway 252 Table 14.22 - Significance of Construction Effects on Surface Water – ERAs, Clockwise Carriageway 255 Table 14.23 - Significance of Construction Effects on Surface Water – ERAs, Anti-clockwise Carriageway 255 Table 14.24 - Significance of construction effects on surface water - slip road widening, clockwise 256 Table 14.25 - Significance of Construction Effects on Surface Water - Slip Road Widening, Anti-clockwise256 Table 14.26 - Significance of Construction Effects on Groundwater – ERAs, Clockwise 257 Table 14.27 - Significance of Construction Effects on Groundwater – ERAs, Anti-clockwise 257 Table 14.28 - Significance of Construction Effects on Groundwater - Slip Road Widening, Clockwise 258 Table 14.29 - Significance of Slip Road Widening Construction on Groundwater (anti-clockwise) 258 Table 14.30 - Significance of Construction Effects on Floodplain – ERAs, Clockwise Carriageway 259 Table 14.31 - Significance of Construction Effects on Floodplain – ERAs, Anti-clockwise Carriageway 259 Table 14.32 - Significance of Construction Effects on Floodplain - Slip Road Widening, Clockwise Carriageway 260 Table 14.33 - Significance of Slip Road Widening Construction on Flood Risk (anti-clockwise) 260 Table 15.1 - Significance Criteria - Cumulative 263 Table 15.2 - Known Major Planned Developments 265 Table 16.1 - Summary of Significant Effects 268 Table 16.2 - Summary of Mitigation Measures 271
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List of Figures – (bound separately – Volume 2) Figure 1.1 M25 Scheme Sections Figure 1.2 Project Location Figure 1.3 Environmental Context Figure 2.1 The Project Figure 5.1 Air Quality Monitoring Locations Figure 5.2 Air Quality Receptors Locations Figure 5.3 200 metre Construction Dust Boundary Figure 5.4 Air Quality: Special Area of Conservation Boundary Figure 6.1 Designated heritage Assets Figure 7.1 Study Area and Landscape Designations Figure 7.2 Landscape Character Areas Figure 7.3 Visual Effects Year 1 Winter Figure 7.4 Visual Effects Year 15 Summer Figure 9.1 Solid and Drift Geology Figure 10.1 Contaminated Land Features Figure 11.1 Noise Study Area, Barriers and Monitoring Locations Figure 11.2 Do Something Noise Levels in 2030 minus Do Minimum 2015 Figure 11.3 Do Something Noise Levels in 2015 minus Do Minimum 2015 Figure 14.1 Water Baseline Conditions Figure 14.2 Existing Drainage
Appendices– (bound separately – Volume 3)
Appendix A Summary of Assessment of Implications on European Sites Appendix B Scoping Consultation Responses Appendix C Air Quality Appendix D Nature Conservation Appendix E Gazetteer of Cultural Heritage Assets Appendix F Visual Impact Schedules Appendix G Drainage Design Input Statement
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1. Introduction 1.1 Project Identification 1.1.1 In 2002, the M25 London Orbit Multi-Modal Study (ORBIT MMS) recommended the provision of additional capacity on the M25 Junctions 23 to 27 (Section 5), generally in the form of one additional lane in each direction. Subsequently, the Advanced Motorway Signalling and Traffic Management Feasibility Study (Department for Transport (DfT), 2008) concluded that Hard Shoulder Running (HSR) could provide a large proportion of the benefits of widening at significantly lower cost. Therefore, the Highways Agency (HA) proposes to provide additional capacity on Section 5 using an Option called Managed Motorway - All Lanes Running (MM ALR). This is referred to hereafter as „the Project‟. Location 1.1.2 The Project is part of the M25. It is within the East of England Region and includes land within the counties of Hertfordshire, Essex and the Greater London Authority. The Project location is shown Figures 1.1 and 1.2. EIA Regulations and Environmental Screening 1.1.3 Environmental Impact Assessment (EIA) in Europe is governed by European Council (EC) Directive No 85/337/EEC, as amended by Council Directive No 97/11/EC and Council Directive No 2003/35/EC of the European Parliament and Council. These Directives are implemented by Section 105A of Highways Act 1980 for Highways Act Projects in England and Wales, as amended by The Highways (Assessment of Environmental Effects) Regulations 1999 (Statutory Instrument 1999 N0. 369) and the Highways (Environmental Impact Assessment) Regulations 2007 (Statutory Instrument 2007 No. 1062). The legal requirement to carry out a statutory EIA and publish an Environmental Statement (ES) only applies to certain highway projects. Highway projects that may require EIA fall into two categories: Annex I – EIA is mandatory for projects that fall into this category. Types of projects included in Annex I are: construction of motorways and new roads and widening. Annex II – A determination process must be followed to decide whether or not EIA is required for Annex II projects. This decision will be based on whether or not the project meets criteria based on the size, location and characteristics of a project; or if the project could have a significant adverse effects on the environment. 1.1.4 The Project has been identified as a „relevant‟ Annex II project due to its potential to have a significant impact upon environmentally sensitive areas and because the development footprint exceeds one hectare. 1.1.5 The process for determining whether or not an EIA will be required is called Screening. The Screening process will culminate in the preparation of a Record of Determination (RoD) and a Notice of Determination (NoD). This is the final stage of Screening and will inform decision makers if the Project requires statutory EIA and the production of an ES. 1.2 Purpose of this Report 1.2.1 This report has been prepared to give an account of the findings of the environmental assessment and is referred to as an Environmental Assessment Report (EAR). The environmental assessment has been carried out to identify the key environmental issues associated with the Project and to determine the need for statutory EIA.
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1.3 Scope and Content Scope 1.3.1 A scoping exercise was carried out in September 2011 to determine the scope of the environmental assessment and the level to which the assessment would be carried out - simple or detailed as defined by the Design Manuel for Roads and Bridges (DMRB). This is discussed in more detail in Section 4.1. Structure 1.3.2 DMRB states that there is no prescribed format for reporting EAR, but suggests a structure which has been mostly followed in this report. This DMRB structure is set out below: Introduction/Overview 1.3.3 Identifies the project and explains the purpose, scope and content of the report. The Project 1.3.4 Explains the background to the project, the regulatory framework, context with Government policies, project description, land use and land take issues and construction, operation and long term management. Alternatives Considered 1.3.5 Description of design options considered. Environmental Impact Assessment Methodology 1.3.6 Description of scoping, survey and methods used, assessment methodology and mitigation and enhancement. Topics 1.3.7 For each separate topic: Study Area; Methodology; Baseline; Value of Resources; Regulatory Framework; Design, Mitigation and Enhancement Measures; Impacts; Significance of Effects; Difficulties Encountered and Summary. Assessment of Cumulative Effects 1.3.8 Description of combined actions on receptors and resources over time, as well as impacts resulting from incremental changes caused by other past, present or reasonably foreseeable actions together with the project. Conclusions 1.3.9 Summary of significant effects and any mitigation measures. References 1.3.10 List of references used throughout the report, broken down by Chapter. Glossary 1.3.11 Common abbreviations and explanation of terminology. Appendices 1.3.12 Includes a summary of the Assessment of Implications on European Sites (AIES) and additional technical information. 1.3.13 Figures that are referred to throughout the report are bound separately as Volume 2.
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Assessment of Implications on European Sites 1.3.14 A screening assessment has been carried out to determine whether the Project will have the potential to cause significant adverse impact on nearby Natura 2000 (European) sites. This is in accordance with DMRB Volume 11, Section 4, Part 1 (HA 2009) Assessment of Implications (Of Highways and/or Road Projects) on European Sites (AIES) also known as Habitats Regulations Assessment (HRA) Screening. The results of this process are reported in the AIES Report and are summarised in Appendix 1 of this report (to follow). Requests for Copies and Additional Information 1.3.15 Copies of the report and further information can be obtained from the Overseeing Organisation. 1.4 The Overseeing Organisation 1.4.1 The Highways Agency is the Overseeing Organisation. The Highways Agency is an Executive Agency of the DfT and is responsible for operating, maintaining and improving the strategic road network in England on behalf of the Secretary of State for Transport. The contact details for the Highways Agency are: Highways Agency
1.5 The DBFO Contractor 1.5.1 The Design Build Finance and Operate (DBFO) Contractor is responsible for the delivery of all M25 Projects and maintenance of the M25 for a 30 year period. Connect Plus was appointed in 2009 by the Secretary of State (SoS) for Transport. 1.5.2 The contact details for the DBFO Contractor are: Connect Plus
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2. The Project 2.1 Background to the Project 2.1.1 The strategic case for providing additional capacity on the M25 was examined in 2002 by the ORBIT Multi Modal Study (MMS). The aim of the ORBIT MMS was to develop a long-term multi- modal strategy for the sustainable management of the M25 and more generally for the transport corridor around London. 2.1.2 On 9th July 2003, the Secretary of State for Transport (SoS) responded to the ORBIT MMS by accepting its recommendation to widen the M25 to four lanes in each direction in a number of places, including Section 5 (the Project). In April 2004, following the SoS decision, the Project entered the Government‟s Targeted Programme of Improvements (TPI). 2.1.3 Following the completion of the Option Identification Stage, the Project entered Option Selection Stage 2 in March 2009. It was included in the January 2009 document „Britain‟s Transport Infrastructure: Motorways and Major Trunk Roads‟ as a Project to begin construction by 2015. The programme assumes a start of works in Nov 2013. 2.1.4 Table 2.1 shows the annual average daily traffic (AADT) figures for the baseline year (2004), as well as forecast AADTs for the Opening Year (2015) and the Design Year (2030) with and without the Project. These are shown for the clockwise (CW) and anti-clockwise (ACW) carriageways on the busiest section between Junction 23 and 24. Table 2.1 - Annual Average Daily Traffic
Baseline (2004) Opening Year (2015) Design Year (2030)
CW ACW CW ACW CW ACW
Do Minimum 74,869 71,026 81,067 78,474 90,257 89,654
Do Something 91,615 87,373 105,038 102,153 2.2 History of the Project 2.2.1 The Highways Agency originally proposed to provide an additional lane on both the clockwise and anti-clockwise carriageways of the M25. This included the 25 km stretch of the M25 between Junctions 23 and 27 (Section 5). The Widening would incorporate the existing climbing lane and recent improvements to two tunnels (Holmesdale and Bell Common). The Widening would tie into the proposed Dual 4-lane Motorway (D4M) section to the west (Section 1, Junctions 16 - 23) and east (Section 4, Junctions 27 - 30). The Widening was designed to alleviate frequent traffic congestion and improve journey time reliability on the M25. The Widening was to be undertaken within the land owned by the HA and was programmed to be completed by 2015. 2.2.2 In December 2004, the Highways Agency made an announcement to progress a number of Widening Projects, including Section 5, under a Design Build Finance Operate (DBFO) contract. 2.2.3 In March 2008, the Advanced Motorway Signalling and Traffic Management Feasibility Study identified Section 5, amongst others, as a preferred candidate for Hard Shoulder Running (HSR). It concluded that HSR could provide a large proportion of the benefits of widening at a significantly lower cost. Having been identified, these „candidates‟ advanced to the „Options Phase‟ where the case for providing additional capacity through HSR in comparison to Widening was further examined. 2.2.4 The results of the Options assessment were presented in the Environmental Support Document (Highways Agency, 2008). This considered the environmental effects of four design options for Section 5, including two HSR options and two Widening options (described in Section 3.1).
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2.2.5 For financial and environmental reasons HSR Base was selected as the Option going forward. A scheme was developed for an option called HSR Base and the environmental effects of this proposal were reported in the Stage 2 Environmental Assessment Report (2010). This scheme was further refined as part of the Stage 3 commission but the scheme was then put on hold in the autumn of 2010 pending the government‟s Comprehensive Spending Review (CSR). In the spring of 2011 the schemes to upgrade the M25 in Section 5 and Section 2 were included in the government‟s plans for transport improvements for this parliamentary session and approval for work on the project to recommence was given. 2.2.6 In December 2011 it was announced that new guidance (CHE Memo 276/11) should be followed whereby Managed Motorway All Lanes Running (MM ALR) would replace Dynamic Hard Shoulder Running with reduced number of signs, gantries and Emergency Refuge Areas (ERAs). An assessment of the minimum improvements needed to deliver safe operation of hardshoulder running and controlled motorway, including through junction running where justified, provides the core element of the proposed scheme.. 2.2.7 At this stage in the Project‟s development, an environmental assessment has been carried out and reported in this EAR. This provides adequate assessment to establish whether significant environmental effects are likely to arise. 2.2.8 The Project is within 2 km of two internationally important designated sites including Lee Valley Special Protection Area (SPA) and Ramsar Site and Epping Forest Special Area of Conservation (SAC). As previously discussed, the Project will be screened in accordance with DMRB guidance for AIES, also known as Habitats Regulations Assessment (HRA) Screening (Appendix 1). 2.3 Regulatory Framework 2.3.1 The UK has a comprehensive planning system which is led at a national level by the recently adopted National Planning Policy Framework (2012). It is a key part of the coalition Governments reforms which aim to make the planning system less complex and more accessible and to promote sustainable growth. It consolidates all policy statements, circulars and guidance documents into a single, simpler Framework. Now adopted, the NPPF replaces all the existing PPSs and PPGs, as well as a number of Circulars. 2.3.2 The Government has committed to revoking the Regional Spatial Strategies under the provisions of the Localism Act (2011) (Clause 89 and Schedule 8). In July 2010 the UK Government formally revoked Regional Spatial Strategies through the Local Democracy Economic Development and Construction Act 2009. However, a high court ruling determined that the Regional Spatial Strategies could not be abolished through this legislation and Regional Spatial Strategies have been reinstated for the time being. However, given the Government‟s commitment, it is assumed that Regional Spatial Strategies will no longer form part of the development plan for the purposes of determining planning applications. 2.3.3 The Development Plan for assessing schemes is considered to be the NPPF and Local Plans. In accordance with DMRB guidance each specialist section refers to international, national and local legislation relevant to that topic. 2.4 Project Objectives Overall Objectives To support and enhance the role of the current M25 as a major national and inter-urban regional transport artery. The scheme shall deliver the minimum scope required to achieve no worsening of safety performance of the network using Managed Motorways techniques.
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To reduce congestion and to develop solutions that provide additional capacity, increase journey time reliability and ensure the safe and economic operation of the motorway. The scheme should make best use of existing infrastructure providing additional capacity within the existing highway boundary, other than in exceptional circumstances. The scheme should be designed to suit the requirements of ongoing maintenance, the needs of Highways Agency‟s Traffic Management and Network Delivery & Development directorates and minimise whole life costs. The project should aim to provide maximum value for money against its whole of life costs in accordance with the Department‟s WebTAG guidance (BCR adjusted for non-monetised impacts should aim to be greater than 2). The scheme should aim to improve on Appraisal Summary Table assessment results produced during the Stage 3 EAR Phase where possible within the constraints of affordability. To deliver the scheme in a way which supports the delivery of the Government's transport policy objectives. Transport & Safety
The scheme should address the transport and safety problems identified in the Challenges and Issues section of this document. To achieve a safety objective under which the "after" accident numbers (per annum) are no greater than those in the "before" and the severity ratio is not increased. The scheme should improve journey time reliability, by improving and better managing traffic flow conditions. The scheme should aim to improve the currency and quality of information provided to drivers about the state of traffic flow on the motorway. Environment To minimise the detrimental environmental effects of the scheme and offset by mitigation measures where technically feasible and economic to do so, taking account of costs, availability of funding and statutory obligations. Economy The scheme should maximise the return on public investment Social and Distributional Impacts
The scheme shall minimise detrimental impacts on vulnerable people groups and provide appropriate mitigation where technically feasible and economic to do so, taking account of costs, availability of funds and statutory obligations. Interfaces
Ensure HA NDD and TMD are consulted and agree with the scheme design and operation. Ensure that the scheme takes into account the capacity improvements planned. Ensure that the adjacent Local Highways Authorities and Emergency Services have input to the scheme design. Standards 2.4.1 Current design standards should be adhered to, except where:
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Changes yield cost savings or additional benefits without affecting the safe operation of the route. The physical characteristics of the route do not suit current design standards. Approval for departures from standard will be sought and gained before any relaxation or departure can be designed into the scheme. 2.5 Any Further Support of Government Policies 2.5.1 The full assessment of the effect of the Project on relevant topic-specific policies is reported under the topic Chapters. 2.6 Project Description 2.6.1 The Project to be carried forward in the Preliminary Design stage of the Project Control Framework (PCF) is based on MM ALR. 2.6.2 An assessment of the minimum improvements needs to deliver safe operation of controlled motorway, including through Junction running where justified has been carried out. MM ALR will provide the core element of the Project and is described below. 2.6.3 MM ALR makes use of the existing hard shoulder to provide the additional lane capacity. This is achieved by providing signals, variable message signs and Emergency Refuge Areas (ERA). Emergency Refuge Areas (ERAs) are provided in accordance with CHE 296/11 approximately every 2.5km where topography and road layout permits. Outside of that required for effective operation of MM ALR, this Project only includes the minimum improvements to the road superstructure (e.g. surfacing, vehicle restraint systems, environmental mitigation and drainage improvements), that would be required to achieve safe and legal operation of Controlled All Lane Running. 2.6.4 MM ALR will be operated between Junctions 23 and 27, with through junction running at Junctions 24 and 26 (i.e. using the hard shoulder through each junction – diverge to merge slips). 2.6.5 At Junction 25 the existing 3 lanes, and 4 lanes through Holmesdale Tunnel will be maintained (lane gain and drop at the Junction 25 merge and diverges). The Bell Common Tunnel that has recently been refurbished will provide 4 lanes and a hard shoulder (presently running with 3 normal lanes and widened hard shoulders and central reserve margins), which will be provided for approximately 500m either side of the tunnel to conform to European codes. Past this area and up to Junction 27 MM ALR will be applied. 2.6.6 A mixture of cantilever and portal gantries will support the signs and signals required for MM ALR. These occur on average every 900m subject to intervisibility. ERAs will be approximately every 2.5kmIn order to accommodate the gantry legs and associated signal equipment cabinets the motorway earthworks will be widened using driven steel sheet piling. At the Junctions there are several merges and diverges that will also be widened using steel sheet piles with any existing drainage and lighting being replaced after widening is complete. 2.6.7 Ducting for communications cables may reuse as much of the existing ducting as possible but in some instances this may not be possible and it may be necessary to clear a 2m wide swath to install ducts in the 2m margin nearest the verge edge. 2.6.8 The proposed detailed drainage arrangements for the Project have not been finalised as yet but would comprise additional gullies at the verge edge to constrain the „flow path‟ of the water in the road edge where necessary and applicable. There would be no additional surfacing to the back of the hard shoulder. The design of the drainage arrangements would be addressed at detailed design stage. The drainage of the ERA‟s will collect the water into 1 or 2 manholes and discharge to the existing networks at a slow rate so as not to overload the drainage system and therefore no
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alteration to the drainage system would be required. All the outfalls to the streams and rivers will remain as existing. 2.6.9 Overall, the proposed drainage system would comprise a combination of: Kerbs and gullies, slot drains and open channels as appropriate and required. The existing carrier drain system would be kept in place for the whole length of the section, and would take the discharge from the collection drain arrangement. 2.6.10 In addition to the implementation of the MM ALR requirements the central reserve will be hardened where it presently is not and a concrete barrier constructed. This will require the removal and replacement of the existing surface water drainage collection system in the central reserve. The drainage networks in the central reserve would remain unchanged 2.6.11 Outline mitigation measures associated with the scheme are described in the topic chapters and would be developed and illustrated further at detail design stage. 2.6.12 No new lighting is proposed for the main line and existing lighting will be retained unaltered unless replacement is required where there is widening. 2.6.13 No new low noise surfacing is proposed with the project but will take place when the maintaining authority (DBFO MAC) has programmed resurfacing works. At present there is approximately some 60 to 70% of “low noise “surfacing on the existing carriageways. 2.6.14 The Project is shown in Figure 2.1. 2.7 Land Use Setting and Land Take 2.7.1 The Project runs for 26 km and is situated entirely within the limits of the Strategic Road Network (SRN) estate. By using the hard shoulder to increase capacity rather than widening, the footprint of the main carriageway will predominantly be un-altered. 2.7.2 The only additional areas of hardstanding will be within the soft estate due to the ERAs as well as minor widening on the approaches to Holmesdale and Bell Common Tunnel portals. There will be 42 ERAs, one approximately every 600 - 800 metres. Each ERA measures 100 x 4.6 metres (460 metres2). The widening at the portal access/egress points will be 500 metres in length and 3.7 metres in width between Chainage 51,550 – 52,050 and 59,930 – 60,430 and 1,100 metres in length and 3.7 metres in width between Chainage 60,900 – 62,000. 2.8 Construction, Operation and Long Term Management Construction 2.8.1 Construction would be phased and is planned to commence in August 2013. The entire section would be constructed by early 2015. 2.8.2 Whilst the final construction sequence is yet to be determined by the contractor and may be optimised / amended, the expectation is that the works to the verges will be carried out in the second phase of each section of the works following the completion of works in the central reserve. When commencing verge works, early attention will be paid to the completion of any necessary environmental mitigation measures which have not been concluded during the central reserve phase or as pre-commencement operations in compliance with the terms of licences secured for the works. Areas of the works which are not affected by environmental constraints will be undertaken at the same time as the mitigation works in the affected areas thereby ensuring efficiency of the operations. 2.8.3 The location of site compounds, access roads, batching plants, storage areas, workforce encampments are not known at this time but environmental consideration / assessment will be a key factor in the selection of chosen sites / routes and in the preparation / mobilisation of facilities
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in accordance with the statutory requirements to minimise adverse effects. It is known that the installation of gantries and ERA‟s will be from the hard shoulder and haul routes for materials and equipment would be along the existing motorway carriageways. 2.8.4 In the event that works are required outside the HA Boundary, for example temporary construction compounds, these works would be agreed with the Local Planning Authority. 2.8.5 All works on site and within the Contractor‟s construction compounds would be undertaken in compliance with a Construction Environmental Management Plan (CEMP). 2.8.6 The basic construction sequence would be determined by the contractor. The location of site compounds, access roads, batching plants, storage areas, workforce encampments are not known at this time. 2.8.7 The effects of the construction of the Project are addressed in each of the topic Chapters. Operational Considerations 2.8.8 MM ALR would operate for 24 hours a day with maintenance operations introducing Traffic Management as appropriate for routine and emergency maintenance The key operational considerations for the MM ALR are as follows: The hard shoulder is no longer available to the maintenance teams during daytime hours, which will result in more activities being carried out at night. There will be safety implications for Traffic Officers and other suppliers working in an environment with heavy traffic flows 7 days a week. MM ALR requires increased resources at the Regional Control Centre (RCC), both in terms of operators and systems support staff. Increased Highways Agency Traffic Officer (HATO) involvement in MM ALR incident control. Increased Technology Managing Agent Contractor (TechMac) cost. Increased impact of system failures. 2.8.9 The effects of the operation of the Project are addressed in each of the relevant topic Chapters. Long Term Maintenance and Repair Strategy 2.8.10 The majority of routine maintenance work will be undertaken overnight. The effect of MM ALR as part of the project and the reduced network space required to undertake the activities will be mitigated. There are exceptions, specifically soft estate maintenance and arboriculture activities, the nature of which will require such activities to be undertaken during hours of daylight and under traffic management. 2.8.11 Soft estate works used to take place from the hard shoulder. Under MM ALR this will not be possible and at certain locations and for certain activities it is possible that vehicles can be parked in ERAs and/or at side roads where over or underbridges occur. Steps down to an access path would be required and operatives can then walk to access areas where maintenance works are required. It is possible that at certain areas, access can also be gained from beyond the HA boundary where there are suitable tracks and the DBFO Contractor will identify such alternative means of access in the Maintenance and Repair methodology. 2.8.12 Routine maintenance activities such as regular inspection will be extended to cover the additional assets for MM ALR as part of the Project. Most inspections are undertaken from vehicles at normal traffic speeds, such as Pavement Condition Surveys and retro reflectivity for white lining. Other assets, such as drainage and the soft estate will require inspection on foot. In such cases the access will be either off-motorway or with the vehicle parked in the ERA. When MM ALR is in operation a safety zone will be in place for operatives inspecting the asset, or inspections will be carried out when MM ALR is not operating.
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2.8.13 Due to MM ALR being in operation 24 hours a day the management of access will need specific procedures for all responsive activities such as: Planned and responsive maintenance Severe weather Incidents Critical / Non Critical faults
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3. Alternatives Considered 3.1 Design Options 3.1.1 In 2008, the HA commissioned an assessment into the feasibility of providing additional capacity on Section 5 through HSR in comparison with Widening. The assessment was reported in the Environmental Support Document (HA, 2008) and compared four different Options. These were: Option 1 - HSR Base Option 2 - HSR Plus Option 3 - Widening Base Option 4 - Widening Plus 3.1.2 The Options are briefly described below. Option 1 - HSR Base 3.1.3 This Option involves the incorporation of the hard shoulder of Section 5 as a running lane during periods of high vehicle flow or incidents by using a system of Active Traffic Management (ATM). A system of gantry mounted signals and message signs manage this Option and are located at approximately the same intervals as ERAs where topography and road layout permits. Other aspects to be considered as part of this Option include in-road detectors to monitor traffic speeds and flows and comprehensive CCTV coverage. Outside of that required for effective operation of HSR, this Option only includes the minimum improvements to the road superstructure (e.g. surfacing, vehicle restraint systems, environmental mitigation and drainage improvements), that would be required to achieve safe and legal operation. Option 2 - HSR Plus 3.1.4 As per Option 1, however, other aspects to be considered as part of this Option include in-road detectors to monitor traffic speeds and flows and comprehensive CCTV coverage. It differs from HSR Base, as outside of that required for effective operation of ATM and HSR, this Option includes other improvements (above the legal minimum) to upgrade the motorway infrastructure to modern standards. These features include drainage, Low Noise Surfacing (LNS) and maintenance lay-bys. Option 3 - Widening Base 3.1.5 This Option involves the construction of an additional lane, widening the carriageway to four lanes in both directions. The edge of the carriageway will generally move outwards by an additional 3.7m on both sides to provide for an additional lane. This Option only specifies the need for the minimum improvements to the road superstructure (e.g. surfacing, vehicle restraint systems, environmental mitigation and drainage improvements), that would be required to achieve safe and legal operation of the motorway (i.e. to provide a direct comparison with HSR Base). Option 4 - Widening Plus 3.1.6 As per Option 3, however, other aspects to be considered as part of this option include upgrading to modern standards. It differs from Widening Base, as outside of that required for effective operation of D4M, this Option includes other improvements (above the legal minimum) to upgrade the motorway infrastructure to modern standards including drainage and LNS (i.e. to provide direct comparison with HSR Plus). Rationale for Selecting Preferred Option 3.1.7 The Environmental Support Document (Highways Agency, 2008) found that the potential environmental impact of Widening was greater than HSR, due to the increased area of soft estate
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that would be turned into additional carriageway. As well as being environmentally preferable compared with Widening, the Advanced Motorway Signalling and Traffic Management Feasibility Study (DfT, 2008) found that HSR could provide a large proportion of the benefits of Widening at significantly lower cost. For these combined reasons, HSR was preferred over Widening for Section 5. The HSR proposals were later developed into MM ALR (in December 2011). MM ALR has fewer gantries and signs than HSR but greater operation and maintenance implications which shall be taken into account in the Operations Report
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4. Environmental Impact Assessment Methodology 4.1 Scoping 4.1.1 As discussed in Section 1.3, a Scoping exercise was undertaken in July 2011 to identify the scope and level to which the assessment would be carried out – simple or detailed (as defined by DMRB). Table 4.1 summarises the Study Area and level of assessment for each topic area. Table 4.1 - Study Area and Level of Assessment by Topic (as defined by DMRB)
Topic Study Area Level of Assessment
Air Quality Cordon for air quality Study Area defined by Detailed traffic data levels of certainty.
Cultural Heritage 500 metres on either side of the centreline of Simple the Project.
Landscape Visual envelope Detailed
Nature Conservation Varies depending on species/habitat Detailed
Geology and Soils 500 metres on either side of the centreline of Simple the Project.
Materials 500 metres on either side of the centreline of Simple the Project.
Noise Roads that are subjected to a change in noise Simple level of more than 1 dB within 2km of the Project road boundary in the Opening Year. This noise change will be established by a 25% increase or 20% decrease in traffic flow forecasts. Noise calculations will be undertaken representing all noise sensitive receptors within 600 metres on either side of the centreline of the Project.
Effects on all 500 metres on either side of the centreline of Simple Travellers the Project.
Community and The National Planning Policy Framework. Simple Private Assets Plans and Policies for Hertsmere Borough Council, Welwyn Hatfield Borough Council, London Borough of Enfield, Epping Forest District Council and Borough of Broxbourne are assessed in each of the relevant specialist topic chapter.
Road Drainage 500 metres on either side of the centreline of Simple and the Water the Project. Environment
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Consultation on Scope 4.1.2 The Scoping Report (Highways Agency, 2010) was sent to the following Statutory Environmental Bodies (SEBs) and local authorities for information: Environment Agency Natural England English Heritage Hertsmere Borough Council Welwyn Hatfield Borough Council London Borough of Enfield Epping Forest District Council Borough of Broxbourne 4.1.3 In addition to the local authorities and SEBs, copies of the Scoping Report were also sent to local representatives of the Campaign for the Protection of Rural England (CPRE) and the City of London Corporation for information. 4.1.4 Comments on the Scoping Report were received from CPRE, English Heritage, Environment Agency, Essex County Council Heritage, Hertfordshire County Council Highways and Natural England. These are included in Appendix B. 4.1.5 A separate appraisal of the effects of the scheme in accordance with the Department for Transport‟s WebTAG methodology has been prepared. This reports the effect of the scheme on the government‟s objectives for transport projects. As required by the DMRB a summary of the air quality appraisal is included in Chapter 5 of this document (to follow) and the WebTAG Appraisal Summary Table (AST) is included as Appendix 4. (to follow) 4.1.6 Following the completion of the EAR and the publication of the NoD on behalf of the Secretary of State, Public Information Exhibitions (PIEs) will be held in the local area. 4.2 Surveys and Predictive Techniques, Method and Constraints 4.2.1 The environmental assessment follows the methodologies outlined in DMRB Volume 11. Further details of the individual assessment methodologies have been provided in the topic Chapters of this report. These include: Spatial scope Surveys and predictive techniques used Regulatory and plans and policies context Constraints 4.2.2 The temporal scope includes the construction period and the operational period as follows: Construction (2014-2015) extends from the commencement of site works to the date immediately prior to opening of the Project. Operation extends from Opening Year (2015) for the remainder of its life. This includes the „Design Year‟ which is 15 years after opening (2030). 4.2.3 Each individual topic section will include, where possible, consideration of impacts from both construction and operation.
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4.3 Changes to DMRB 4.3.1 Changes made to Volume 11 of the DMRB in 2009 introduced alterations to the original topic areas. Several topic areas from the original DMRB have been superseded (or altered in the case of Geology and Soils), these include the following: Vehicle Travellers Land Use Pedestrians, Cyclists, Equestrians and Community Effects Impact of Road Schemes on Policies and Plans Geology and Soils 4.3.2 These topic areas have been merged into the following headings: Effects on All Travellers Community and Private Assets Materials (including Contaminated Land) Geology and Soils (excluding Contaminated Land) 4.3.3 Where detailed methodologies for the new topic areas were not available those existing found within DMRB Volume 11 Section 3 were used. A more detailed explanation of the methodologies used for new topic areas will be made within the individual Chapters. 4.4 Significance Criteria 4.4.1 The approach for determining significance of effects broadly follows the guidance provided in DMRB Volume 11, Section 2, Part 5 (HA 205/08), IAN 125/09 and IAN 126/09 and was defined in the Environmental Assessment Scoping Report (September 2011) produced for this Project. 4.4.2 Guidance for determining significance of effects for some environmental topics has been provided in DMRB Volume 11, Section 3. Where applicable, this has been referred to in the relevant specialist sections of the EAR. 4.4.3 Where significance criteria have not yet been developed in DMRB Volume 11 for particular environmental topic, the approach for determining significance of effects has been defined within the relevant specialist sections of the EAR. 4.5 Mitigation and Enhancement 4.5.1 Elements of environmental mitigation and drainage improvements were considered where deemed necessary to mitigate potentially significant environmental impacts. This is discussed within the specific topic Chapters.
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5. Air Quality 5.1 Introduction 5.1.1 This chapter presents the air quality assessment for the scheme. The assessment addresses local air quality effects in-terms of human health and sensitive vegetation; regional air quality in-terms of emissions; and construction dust effects. 5.1.2 Key tables are included within this volume of the report (Volume 1b). Figures illustrating the study area and receptors are included in Volume 2. Supporting information is included for reference in Volume 3. 5.2 Study Area Local Air Quality – Study Area 5.2.1 The extent of the local air quality study area has been defined by the roads that would be affected by changes in traffic due to the scheme. Affected roads have been identified according to scoping criteria given in the Design Manual for Roads and Bridges (DMRB) Volume 11, Section 3, Part 1 (DMRB HA207/07) (Ref 5.1), paragraph 3.12. These roads are referred to as the local air quality Affected Road Network (ARN). For further details of ARN scoping criteria, refer to Section 5.3 „Methodology‟ below and additional data in Box A5.2 in Appendix 5 Volume 3, which includes thematic maps of the local air quality ARN, the assumptions used, and a table of data defining the local air quality ARN. 5.2.2 The local air quality study area extends to 200 metres („m‟) either side of the ARN. Beyond this distance the influence of a particular road on local pollutant concentrations will be indistinguishable from background concentrations and the scheme effect will be negligible. Within 200 m, the local air quality study area includes locations that are potentially sensitive to changes in air quality (termed „receptors‟). Receptors relate to relevant human exposure (i.e. human health) and nature conservation sites that have statutory designation (termed „Designated Sites‟). Designated Sites include Sites of Special Scientific Interest (SSSI), Special Areas of Conservation (SACs), Special Protection Areas (SPAs) and „Ramsar‟ sites where the designated features are sensitive to air pollution. 5.2.3 For the scheme, the local air quality ARN has been defined as: the M25 mainline carriageway from Junction 16 (M40) to Junction 31 (A13 at Grays) and associated on and off slip roads at junctions 22, 23, 25, 26 and 27; the A1081 and A414 between M25 Junction 22 and M1 Junction 7; the A1 from north of Apex Corner (south of the M25) to A1(M) Junction 3 (north of the M25); the A10 immediately north and south of the M25 Junction 25; and the M11 from Junction 5 (Chigwell) south of the M25 to Junction 8 (Bishops Stortford) north of the M25. 5.2.4 An overview of the local air quality (human health) study area is given in Figure 5.1. This shows the extent of the ARN as well as constraints (Air Quality Management Areas (AQMA) and Designated Sites). Receptor locations included in the assessment are shown in Figure 5.2. 5.2.5 There are four Designated Sites within 200 m of the ARN, three of which are sensitive to air pollution. These are shown in Figures 5.1 & 5.3. Regional Air Quality – Study Area 5.2.6 The extent of the regional air quality study has been determined according to assessment scoping criteria given in DMRB HA207/07, paragraph 3.20. The assessment considers the potential
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changes in emissions in terms of overall improvement or deterioration. For further details refer to in Appendix 5, Volume 3, Box A5.1 which includes a thematic map of links within the regional ARN and a table of traffic data defining the regional ARN. Construction Dust – Study Area 5.2.7 The study area for construction effects has been defined in accordance with DMRB HA207/07, paragraph 3.45 and is shown in Figure 5.4. 5.3 Baseline Conditions Local Air Quality – Human Health 5.3.1 Baseline local air quality conditions are described in terms of concentrations of certain substances within the air that surrounds us in the outdoor environment (termed „ambient air‟), which can affect
human health, primarily nitrogen dioxide (NO2) and particulate matter as PM10. The conditions are given context by comparing the concentrations to criteria that have been set to protect public health. 5.3.2 The UK Government has set out in legislation requirements to manage local air quality for the protection of public health. The Governments Air Quality Strategy (AQS) (Ref. 5 2) includes concentration targets for local air pollutants, which are referred to in this assessment as „AQS objectives‟. Where a local authority determines that an AQS objective is not being met, it is required to declare an Air Quality Management Area (AQMA) and implement an Action Plan to achieve improvements. In addition to the AQS objectives, the UK Government is required through European Union (EU) legislation to ensure compliance with concentration thresholds for local air pollutants, known as „Limit Values‟ (Ref. 5.3). Most concentration thresholds for Limit Values and AQS objectives are the same; the dates in which they come into force, however, are different. Section 5.5 on the regulatory and policy framework provides further details. 5.3.3 Local air quality conditions are determined by sampling the air to measure actual pollutant concentrations or through modelling to estimate concentrations. Both techniques are used by local authorities and the Highways Agency. The information collated by these organisations therefore provides a reasonable basis for defining baseline conditions. Air Quality Management Areas 5.3.4 The local air quality study area for the scheme is within the boundaries of sixteen local authority areas: South Buckinghamshire District Council (ref.5.4); Chiltern District Council (ref.5 5); Three Rivers District Council (ref.5.6); Dacorum Borough Council (ref 5.7); St Albans City and District Council (ref.5.8); Hertsmere Borough Council (ref 5.9); London Borough of Barnet (ref 5.10); Welwyn Hatfield Borough Council (ref 5.11); Broxbourne Borough Council (ref.5.12); London Borough of Enfield (ref 5.13); Epping Forest District Council (ref.5.14); Harlow District Council (ref.5.15);
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Uttlesford District Council (ref 5.16); London Borough of Havering (ref.5.17), Brentwood Borough Council (ref 5.18); and Thurrock Council (ref.5.19). 5.3.5 The aforementioned local authorities carry out regular reviews and assessments of local air quality. This process has shown that the air pollutants most likely to exceed the relevant air quality
objectives associated with road traffic emissions are nitrogen dioxide (NO2) and fine airborne particulate matter (PM10) for the 24 hour mean. Relevant criteria are given in Table 5.1. Table 5.1: Relevant local air quality criteria (human health) Pollutant Air Quality EU Limit Measured as Date to be Date to be Objective Value achieved by achieved by (AQS (EU Limit Concentration Objective) Value) Nitrogen 200 µg/m³ 200 µg/m³ 1-hour mean; not to be 31/12/2005 01/01/2010 dioxide exceeded more than (NO2) 18 times a year 40 µg/m³ 40 µg/m³ Annual mean 31/12/2005 01/01/2010 Particles 50 µg/m³ 50 µg/m³ 24-hour mean; not to 31/12/2004 01/01/2005 (PM10) be exceeded more than 35 times a year 40 µg/m³ 40 µg/m³ Annual mean 31/12/2004 01/01/2005
5.3.6 The local air quality ARN crosses through, or within 200 m of 21 AQMA‟s. All AQMA declared for
NO2 relate to indicated exceedances of the AQS annual mean objective threshold. The AQMA for PM10 relate to indicated breeches of the 24 hour mean AQS objective threshold. The relevant AQMA are listed in Table 5.2 below. The locations are shown in Figure 5.1. Table 5.2: AQMA within 200 m of the ARN AQS Date of Local authority Name objective Description declaration exceeded
South South Bucks NO Annual An area comprising the M4, M25 and Buckinghamshire 2 2004 AQMA Mean M40 and adjacent land District Council
Along the M25 from just south of M25 Chorley Wood NO Annual J18 to just north of where the motorway 2 2001 NO2 AQMA Mean crosses the River Chess extending 74 m either side of the centreline A slightly narrower area from just north of M25 J18, along the M25 to just north Chorley Wood PM 24 Three Rivers 10 2001 of where the motorway crosses the PM AQMA hour mean District Council 10 River Chess extending 38 m either side of the centreline An area along the M25 from just west Chandlers of where Chandler's Lane crosses the NO Annual Cross NO 2 2001 M25 to the beginning of M25 J19 2 Mean AQMA extending 74 m either side of the centreline
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AQS Date of Local authority Name objective Description declaration exceeded Chandlers A slightly narrower area than that for PM 24 Cross PM 10 2001 NO extending 38 m either side of the 10 hour mean 2 AQMA centreline. Near M25 J19 An area surrounding where the M25 Kings Langley NO Annual crosses the railway extending 74 m 2 2001 NO2 AQMA Mean either side of the centreline. To the east of M25 J20 Residential properties in Frogmore and St Albans NO Annual 2 2002 Colney Street along the A5183. AQMA No. 7 Mean St Albans City Between M25 J21a and J22 and District The area comprising of Beechtree Council St Albans NO Annual Cottages, Hemel Hempstead Road, St. 2 2004 AQMA No. 2 Mean Albans (adjacent to junction of M1(J7) and A414). Hertsmere NO Annual Includes nos. 31-39 Blanche Lane, 2 2002 AQMA No. 3 Mean South Mimms. West of M25 J23
A single residential property 'Charleston Hertsmere Hertsmere NO Annual 2 2002 Paddocks', St Albans Road, South Borough Council AQMA No. 2 Mean Mimms, Potters Bar. East of M25 J23
Residential properties at nos. 23-27 Hertsmere NO Annual 2 2002 Dove Lane and caravan site off A1000 AQMA No. 1 Mean Barnet Road. West of M25 J24 NO Annual 2 The whole borough. In terms of the London Borough Mean, PM Barnet AQMA 10 2001 ARN, the AQMA is associated with the of Barnet 24 hour A1 Barnett bypass south of the M25 mean An area incorporating Tile Kiln Cottage No.3: Tyle Kiln NO Annual 2 2001 on Burntfarm Ride, just north of the Cottage Mean M25. Between M25 J24 and 25 Properties nos. 33 to 55 Teresa No.2: Teresa NO Annual Gardens, Waltham Cross. Adjacent to 2 2001 Broxbourne Gardens Mean western portal of M25 Holmesdale Borough Council tunnel A number of residential properties close NO2 Annual to the M25, including Arlington No.1: Arlington Mean , Crescent, Parkside and nos. 13-21 2001 Crescent PM10 24 High Street, Waltham Cross. Adjacent hour mean to eastern portal of M25 Holmesdale tunnel NO Annual 2 Whole borough designation. Located London Borough Mean , Enfield AQMA 2001 immediately south of the M25 between of Enfield PM 24 10 J24 and midway between J25 and J26 hour mean The AQMA comprises parts of Brook Brentwood NO Annual 2 2005 Street, Brentwood and the A12. To the AQMA No. 2 Mean Brentwood east of M25 J28 Borough Council The AQMA comprises parts of Nags Brentwood NO Annual 2 2005 Head Lane, Brentwood and the M25. AQMA No. 1 Mean To south of M25 J28
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AQS Date of Local authority Name objective Description declaration exceeded NO Annual 2 Whole borough designation. Located London Borough Mean , Havering AQMA 2006 immediately west of the M25 to the of Havering PM 24 10 north of and including M25 J28 hour mean Near to M25 between J29 and J30 on Thurrock AQMA NO Annual Thurrock Council 2 2001 edge of Irvine Gardens, South No. 15 Mean Ockendon. Kemps Farm Cottage off Dennis Road, Thurrock AQMA NO Annual 2 2001 South Ockendon, east of the M25 No. 16 Mean between J29 and J30.
5.3.7 South Buckinghamshire District Council has declared one AQMA found within 200 m of the local air quality ARN. The section of the AQMA within 200 m of the local air quality ARN and addressed in this assessment includes the area around M25 Junction 16 following the M25 north to the district boundary. 5.3.8 Three Rivers District Council has declared five AQMAs; all are associated with the M25 motorway as the dominant source of pollutants. 5.3.9 St Albans City & District‟s AQMA no.7 was declared on the basis of predicted exceedances of the
annual mean NO2 AQS objective and is attributed to emissions from traffic on the M25. Monitoring and modelling of NO2 concentrations within AQMA No. 2 indicated exceedances of the annual mean NO2 AQS objective were attributed to emissions from the A414 and M1 around Junction 8. 5.3.10 Three of Hertsmere Borough Council‟s six AQMAs (No.s 1- 3) are next to and directly associated with emissions from the M25. 5.3.11 The London Boroughs of Barnet, Havering and Enfield have all declared their entire borough‟s as AQMAs. While the M25 is a contributing source in at least part of the AQMAs, it is not the sole (nor necessarily the primary) reason for declaration. 5.3.12 Broxbourne Borough Council declared AQMA Nos 1,2 & 3 for predicted exceedances of the
annual mean NO2 AQS objective, in addition AQMA No.1 was also predicted to exceed the daily mean PM10 objective. All three AQMAs are located next to the M25 and attributed to emissions mainly from the M25. 5.3.13 Brentwood Borough Council have declared two of their seven AQMAs next to the M25. Other AQMAs are at busy local road junctions or near to the A12 as a source, but are not within the ARN for this scheme. 5.3.14 Thurrock has declared two AQMA located within 200m of the local air quality ARN. AQMA No.15 & 16 are located within 200 m of the M25 between Junction 29 and 30. 5.3.15 Chiltern District Council, Dacorum Borough Council, Welwyn Hatfield Borough Council, Epping Forest District Council, Harlow District Council and Uttlesford District Council have not identified any exceedances of the AQS objectives at relevant receptors in the vicinity of the modelled sections of the local air quality ARN. There are no AQMA‟s declared which are required to be taken into consideration in respect of the current assessment work. Monitoring 5.3.16 Extensive air quality monitoring within the scheme corridor has been undertaken by local authorities and the Highways Agency. This information has been collated to consider baseline
local air quality conditions. Further monitoring to determine annual mean NO2 concentrations is underway in the vicinity of Bell Common Tunnel; so far, monthly average data have been collected for November and December 2011 and January, May, June and July 2012.
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5.3.17 Ratified data from monitoring surveys can be compared with the relevant local air quality criteria including AQS objectives and mandatory EU Limit Values, which are given in Table 5.1. The
monitoring techniques used for NO2 are both continuous and passive, for PM10 the monitoring is continuous. Continuous monitoring methods measure concentrations automatically and report concentrations at least every hour. Passive monitoring methods involve exposure of sampling devices such as diffusion tubes over a longer time period (typically a 4 week period) and returning the device to a laboratory for analysis to derive an average concentration over the sampling period. Continuous monitoring methods are generally more accurate than passive techniques so consideration of the associated uncertainties is important when undertaking air quality assessment.
5.3.18 It is standard practice to adjust the annual mean NO2 concentration data derived from passive diffusion tube measurements by applying a correction factor to compensate for differences in readings compared to the reference method. This process, termed „bias adjustment‟, involves applying a bias adjustment factor which has been derived from co-locating diffusion tubes with
one or more continuous analyser. Bias adjustment factors for NO2 can be derived by local co- location studies or by using DEFRA‟s national bias adjustment factor dataset (ref 5.20), which is periodically updated with data submitted from local authority co-location studies. Also, unlike continuous analysers, diffusion tubes cannot provide data for short term periods; nevertheless, they are an important means for measuring annual mean local air quality concentrations. 5.3.19 The Highways Agency has sought guidance from the local authorities on the appropriate bias adjustment of their diffusion tube data to assume in the modelled base year for this assessment. Their responses have been accounted for in the data used in the assessment and as presented in this report. With regard to the project specific monitoring the set of bias adjustment factors as published by DEFRA (ref. 5.20) has been used. 5.3.20 Until the end of 2009 there were two continuous analyser sites within 200 m of the ARN. One site was located at Arlington Crescent, Waltham Cross (adjacent to the eastern portal of Holmesdale Tunnel) operated by Kings College Environmental Research Group (ERG) as part of the „Herts and Beds‟ Air Quality monitoring network. The site was decommissioned at the end of 2009. The other site was located at Gerrards Cross and operated on behalf of South Buckinghamshire District Council. Data capture for this site was below 75% in 2008, therefore it has been excluded from the model verification process. Data for these sites are given in Table 5.3 as part of the baseline.
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Table 5.3: Arlington Crescent continuous analyser (BBCMS) statistics Pollutant Statistic 2006 2007 2008 2009 2010 Arlington Crescent
Annual mean 48 42 37
Number of exceedances of NO 2 hourly mean threshold of 200 0 0 0 µg/m3 (18 allowed) Data capture 94% 99% 99% Site closed Annual mean 27 (31) 24 (27) 22 (25)
Number of exceedances of PM [i] 10 24-hour mean threshold of 50 15 (26) 18 (12) 5 (6) µg/m3 (35 allowed) Data capture 94% 98% 93% Gerrards Cross Annual mean 39 41 37 38 41 Number of exceedances of NO2 hourly mean threshold of 200 0 0 0 11 3 µg/m3 (18 allowed) Data capture 86% 88% 74% No data 81% 22 21 Annual mean 23 (26) 22 (25) 21 (24) (No data) (No data) Number of exceedances of PM 10 hourly mean threshold of 200 7 14 8 0 1 µg/m3 (18 allowed) Data capture 88% 98% 95% No data 99% Notes: [i] TEOM PM10 analyser results shown as converted to reference equivalent using the volatile correction method. Values in brackets ( ) are using the superseded TEOM * 1.3 method
Data source: Herts & Beds Air Quality Network http://www.hertsbedsair.org.uk/hertsbeds/asp/home.asp This site is now closed, replaced with http://hertsbedsair.net/ „No data‟ indicates parameter not available in published reports. Values in italics indicate that data capture was less than the recommended 75% and results should be taken as indicative only.
5.3.21 Annual mean NO2 concentrations have been monitored using diffusion tubes at 135 sites within 200 m of the roads comprising the local air quality ARN by the local authorities and Highways Agency. The latter are from an extensive monitoring campaign for the M25 sections 1 and 5 between 2006 and 2009 inclusive. Volume 3, Appendix 5, Table A5.1 gives details of the 135 site locations (as shown in Figure 5.2) and Table 5.4 gives the annual mean concentrations for 2006 to 2010, running through the local air quality ARN from east to west. 104 of the sites are Highways Agency sites and 31 are local authority sites. Monitoring data from relevant local authorities for the year 2011 were not available at the time of writing as these were still being processed to be reported in statutory LAQM Updating and Screening Assessments for 2012. Monitoring by the Highways Agency was discontinued after 2009 with only the 31 local authority sites remaining. 5.3.22 Details of the bias adjustment factors that have been applied to determine these results are given in Volume 3, Appendix 5, Table A5.2.
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Table 5.4: Annual mean NO2 concentrations (µg/m³) at diffusion tubes within 200 m of the ARN (after bias adjustment)
ID 2006 2007 2008 2009 2010 SBDT6 38.6 42.5 46.4 41.2 43.2 SBDT18 43.9 37.6 45.8 No data 43.3 HyDT10 33 29.8 36.9 30 Closed HyDT11 37.6 37.7 41 33.6 Closed HyDT12 35.8 36.5 41.2 34.1 Closed HyDT9 54.9 49.4 50.1 40.3 Closed HyDT8 32.6 35.9 43.8 32.9 Closed HyDT13 28 23.7 28 28.5 Closed HyDT14 31.6 28.5 32.2 30.6 Closed HyDT40 23.5 25.1 25.9 23 Closed HyDT34 26 21.1 23.6 21.9 Closed HyDT35 24.7 22.6 26 26.7 Closed HyDT32 35.6 38.9 38.7 31.8 Closed HyDT33 38.7 40.2 41 35.9 Closed HyDT31 41 36.9 40 32.6 Closed HyDT30 35.2 39.3 39.7 30 Closed HyDT29 37.4 34.3 39.5 32.9 Closed HyDT28 38.3 38.9 44.5 35.1 Closed HyDT37 28.4 26.5 30.8 26.6 Closed HyDT36 37.4 38.3 40.3 37.7 Closed HyDT38 86 80.8 87.5 67.9 Closed HyDT39 89.5 82.2 82.3 84.1 Closed HyDT18 26.7 26.6 28.4 25.6 Closed HyDT17 27.4 27.8 30.6 26.5 Closed HyDT50 29.8 36 34.4 28.9 Closed HyDT63 41.5 41.7 37.8 41.1 Closed HyDT64 38.5 37.8 46 37.2 Closed HyDT65 27.7 23.9 26.3 22.6 Closed HyDT51 28.6 25.1 28.3 24.1 Closed HyDT52 23.8 22.1 22.5 20.5 Closed HyDT48 37.8 29.8 37.2 30.3 Closed HyDT49 30.5 25.7 33.1 27.9 Closed HyDT41 37.6 38.8 42.1 35.1 Closed HyDT42 31.9 34.3 35.3 30.4 Closed HyDT43 35.2 32.9 34.7 29.5 Closed HyDT44 34.5 29.9 36.1 29.4 Closed HyDT45 32.6 27 31.6 28.2 Closed HyDT47 24.2 21.6 24.6 22.6 Closed HyDT106 52.1 52.2 55 47.3 Closed HyDT105 38 34.8 37 31.6 Closed HyDT75 37.4 34.9 36.5 37.7 Closed HyDT76 36.9 33.9 37.4 30.4 Closed HyDT77 37.7 32.6 36.2 33 Closed HyDT67 34.5 31.5 35.4 31.9 Closed HyDT73 37.1 32.6 38.7 30.7 Closed HyDT80 37.1 31.5 34.2 30.9 Closed HyDT81 39.4 36.6 37.9 35.4 Closed HyDT84 34 35.1 31.5 27.4 Closed
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ID 2006 2007 2008 2009 2010 HyDT79 34.2 33 36.6 31.7 Closed HyDT78 35.8 30.6 32.9 30.4 Closed HyDT141 36.1 31.7 39.9 34.6 Closed HyDT160 29.6 31 31.6 30.5 Closed SADT125 35.7 33.4 38.4 37 39.7 SADT124 40.8 46.9 44.3 40.6 43 HyDT174 41.6 39 43.1 36.7 Closed HyDT176 36.5 38.6 43 35.2 Closed SADT123 39 43.3 42.2 46.6 41.8 HyDT136 33.5 33.7 39.8 30.1 Closed SADT117 33 34.1 33.4 33.2 34.1 HMDT60 37.2 38 36.3 31.8 35 HyDT134 37.6 34.2 35.8 31.1 Closed HyDT126 29 29.8 29.4 24.2 Closed HyDT125 32.2 32.4 28.4 24.6 Closed HyDT124 33.6 32.8 33.8 30.3 Closed HyDT108 49.9 46.9 47.9 37.1 Closed HyDT123 32.5 32.2 33.9 30.4 Closed HMDT61 53.4 52.3 55.2 46.6 48.8 HyDT116 53.1 38.3 53.5 47 Closed HyDT117 60.2 46.4 43.8 40.9 Closed HyDT115 55.4 43.4 48.5 41 Closed HyDT114 56.8 42.7 48.3 42.7 Closed HyDT119 42.8 39 46.6 41.6 Closed HyDT113 49.6 36.6 44.6 36.9 Closed HyDT112 46.4 34.7 43.7 33.8 Closed HyDT118 58 45.6 54.1 48.7 Closed HMDT86 No data No data 56 41.8 52 HyDT186 39.9 33.3 40.2 32.7 Closed HyDT185 42.9 34.1 41.4 35.6 Closed HyDT184 42.6 35.1 42 37.1 Closed HMDT63 45.5 41.9 45.9 42.7 41 HyDT183 44.6 38.8 48.7 41.4 Closed HMDT43 52.8 50.7 57.7 53.3 Closed BBDT25 No data No data No data 26.6 No data HyDT255 29.4 33.5 31.3 28.1 Closed HyDT246 45.2 44.2 49.8 38.1 Closed HyDT247 41 38.2 42.3 35.9 Closed EnDT7 No data 36 35 30 38 HyDT239 40 38.9 41.2 34.4 Closed HyDT240 44.2 36.4 40.8 32.6 Closed HyDT241 35.4 32.6 37.9 30.5 Closed BBDT10 41.2 33 38.1 29.2 No data HyDT226 48.6 38.9 42.1 37 Closed HyDT225 34.9 31.9 42.1 29.9 Closed HyDT227 32.5 29.2 35.2 30.8 Closed HyDT242 31.9 31.8 36.2 33.7 Closed HyDT243 33.9 32.4 34.9 31.8 Closed HyDT230 36.4 32.5 35.5 30.5 Closed BBDT11 No data No data 42.9 No data No data EppDT383940 No data No data No data 41 45
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ID 2006 2007 2008 2009 2010 BBDT17 No data No data 41.5 No data No data HyDT231 52.9 49.1 53.5 49.2 Closed BBDT05 47.7 No data 62.2 No data No data HyDT259 36.2 37.6 41.5 31.9 Closed EppDT7 No data 37 33 34 37 EppDT6 39 No data 37.8 No data No data HyDT207 47.8 49.1 50.4 41.4 Closed EppDT32 No data No data 37.1 No data No data EppDT313237 No data 40 37 37 39 EppDT36524 35.5 38.4 36.1 36.3 38 HyDT209 32.6 38.1 35.1 28.5 Closed HyDT213 30.3 28.8 34.8 32.6 Closed HyDT217 58.6 51 64.6 48.7 Closed HyDT216 57.5 65.1 55.5 46.6 Closed HyDT215 53.8 41.8 73.8 38 Closed HyDT220 46 43.1 47.2 36.8 Closed HyDT219 53.1 60.3 58.4 46.4 Closed HyDT218 56.3 59.7 67.7 41.9 Closed HyDT214 37.4 35.1 43.8 50.7 Closed HyDT221 39.3 34.9 47.3 43.8 Closed HyDT222 45.5 43.7 53.5 48.9 Closed HyDT223 37.2 35 40.1 37.7 Closed HyDT203 30.4 31.1 44.2 31.8 Closed HyDT202 38.3 45.5 48.4 41.2 Closed EppDT2123 No data No data 35.6 No data No data HyDT201 41.3 38.1 46.8 38.2 Closed HyDT191 32.4 34.2 33.6 31.8 Closed HyDT192 31.3 33.1 34.9 30.9 Closed BRWDT4 47.1 45.6 54.9 42.6 31.7 BRWDT5 47.7 47 57.3 45.8 53.5 BRWDT7 34.3 30.9 36.5 29.3 33.1 THDT7 38.9 39.2 35.4 33.4 30.5 THDT9 39.7 41.5 34.9 36.1 32.5 EppDT11 30 31 30.1 31 31 EppDT3 31 30 29.5 38 No data UTDT8 30.7 28.1 35.7 31 36.2 Notes: Values in bold indicate exceedances of the 40 µg/m³ AQS objective for annual mean NO2. „No data‟ indicates that monitoring was not available at that location in that year. „Closed‟ indicates that monitoring was not undertaken at that location in that year. Values in italics indicate that data capture was less than the recommended 75% and results should be taken as indicative only. Enfield Council only report monitoring to one decimal place.
5.3.23 The NO2 tube monitoring data presented in Table 5.4 has been reviewed to identify monitoring sites which exceed the 40 µg/m³ AQS objective for annual mean NO2. The locations and results at these sites are discussed in more detail below. 5.3.24 SBDT6 is situated 137 m to the east of the M25 in Tatling End, Gerrards Cross, about 6 m from the A40 Oxford Road. The nearest relevant exposure is at a residential properties around 30 m from the diffusion tube across the A40. The relatively high concentrations at the site are likely to
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be mainly due to road-traffic emissions from the A40 and it is unlikely that traffic from the M25 contributes significantly, given the distance from the site to the motorway. 5.3.25 SBDT18 is also located in Gerrards Cross, 53 m to the east of the M25, within South Bucks AQMA. The site is adjacent to a Fire Station about 15 m from the A40 Oxford Street. The nearest relevant exposure is at a residential properties around 40 m from the diffusion tube across the A40. The relatively high concentrations at the site are likely to be due to the combination of road- traffic emissions from the A40 and the M25. 5.3.26 HyDT10, HyDT11 and HyDT12 are located along Shepherd‟s Lane, which crosses the M25 between Junction 17 and 18. The monitoring sites are sited at increasing distances from the M25 of 33 m, 46 m and 77 m respectively. The nearest relevant exposure is at residential properties on
Chiltern Drive off Shepherds Lane approximately 165 m from the M25. NO2 concentrations greater than 40 µg/m³ were reported at the two monitoring sites furthest from the M25, in 2008 only, possibly due to the effect of the M25 being elevated relative to the monitoring site closest to the M25. All other years and sites recorded concentrations below 40 µg/m³. 5.3.27 HyDT9 and HyDT8 are located off The Queens Drive to the east of the M25 between Junction 17 and 18. HyDT9 is located only 27 m from the M25. The nearest receptor is the property façade at
D1S1R1, which is approximately 65 m from the M25. NO2 concentrations greater than 40 µg/m³ were reported from 2006 to 2009, though much reduced in 2009 compared to other years. HyDT8 is located 92 m from the M25 and represents concentrations at the residential property facades
adjacent to The Queens Drive. NO2 concentrations greater than 40 µg/m³ were reported in 2008 only, a year which appeared to have higher concentrations in this locality (see results for HyDT10, HyDT11, HyDT12, HyDT13 and HyDT14).
5.3.28 HyDT33, HyDT32 and HyDT31 are found along Park Avenue within the Chorleywood NO2 AQMA declared by Three Rivers District Council around M25 Junction 18. HyDT33 is 35 m from the M25 and is representative of the closest receptor D1S4R1. Concentrations are over 40 µg/m³ in 2007 and 2008. HyDT32 is located at a similar distance from the M25, but does not exceed 40 µg/m³ in any year. HyDT31 is located at similar distances from the M25 but is also within 100 m of the
A404 which crosses under the M25 to north east. NO2. Concentrations greater than 40 µg/m³ were observed at HyDT31 in 2006 and 2008. Concentrations at HyDT32 and HyDT33 are likely to be due to road-traffic emissions from the M25 only, whilst HyDT31 could also be affected by emissions from the A404.. 5.3.29 HyDT28, HyDT29 and HyDT30 are located along the northern section of Park Avenue as it approaches the A404 Rickmansworth Road. HyDT28 is representative of the boundary of the property on Park Avenue nearest to the M25 and is similar to receptor D1S5R1, which is 85 m from the M25 and 25 m to the north of the A404, and so the A404 will influence its results.
HyDT28 recorded NO2 concentrations greater than 40 µg/m³ in 2008 only. 5.3.30 HyDT36 and HyDT37 are located on the western side of M25 Junction 18, and are likely to be influenced by road-traffic emissions from the M25 including junction slip roads and the A404. HyDT36 represents the boundary of the property on Parkfield closest to Rickmansworth Road and the M25 and recorded concentrations greater than 40 µg/m³ in 2008 only. HyDT37 represents the facade of the nearest property on Parkfield to the A404 and Junction 18 and recorded much lower concentrations than HyDT36 between 2006 and 2009. 5.3.31 HyDT38 and HyDT39 are both located on the roadside of the M25 where the lanes merge north west of M25 Junction 18, within 9 m of the road. Both locations reported very high concentrations
of NO2 between 2006 and 2009, though they do not represent concentrations at the closest property façade to the M25 on Wyatt‟s Close which is 40 m from the carriageway. 5.3.32 HyDT50, HyDT63, HyDT64 and HyDT65 are a group of monitoring sites found on the eastern side
of the M25 at the northern extent of Chorleywood NO2 AQMA. HyDT63 and HyDT64 are the closest to the M25 at 12 m and both locations recorded high NO2 concentrations between 2006 and 2009 as a result of close proximity to the M25, although the range of results at these co-
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located tubes indicates that an average value would have been lower in each year. The results from HyDT50 and HyDT65 located at approximately 20m and 70m from the M25 respectively were much lower than 40 µg/m³, indicating that the nearest property façade, 60 m from the M25, is likely to be lower than 40 µg/m³. 5.3.33 HyDT41, HyDT42 and HyDT43 are a small group of monitoring sites representing the eastern side
of Chandlers Cross NO2 AQMA (associated with road-traffic emissions from the M25) in Three Rivers District Council. HYDT41 is the only tube to record NO2 concentrations greater than, 40 µg/m³.reported in 2008 only. The nearest receptor is D2S3R1 which is 10 m further away from the M25 than HyDT41 and more fairly represented by concentrations at HyDT42 which are lower than 40 µg/m³. 5.3.34 HyDT106 is 133 m from the M25 at Junction 20 but is also within 5 m of the A41 which is more
likely to explain the high concentrations of NO2 every year between 2006 and 2009. 5.3.35 SADT124 / HyDT174 and HyDT176 / SADT123 are located to the south and north of the M25
around St Albans AQMA No7 respectively. SADT124 has experienced high concentrations of NO2 between 2006 and 2010, and is 68 m from the M25. HyDT174 recorded similar concentrations. To the north of the M25, HyDT174 and SADT123 are located within the St. Albans AQMA No.7 which is associated with the A5183. HyDT174 recorded high concentrations in 2008 only, whilst SADT123 reported high concentrations for 2007 to 2010. 5.3.36 HyDT108 and HyDT123 are located south west of the M25 eastbound carriageway west of Junction 23. High concentrations were reported at HyDT108 between 2006 and 2008 as a result of emissions from the M25. However receptor D6S1R1 represents the nearest property façade to the M25 at this location, which is a similar distance from the M25 to HyDT123 where concentrations were lower than 40 µg/m³. 5.3.37 HMDT61, and HyDT112 to HyDT119 are all located to the north east of the M25 carriageway around Hertsmere AQMA No.3, associated with the South Mimms area of the M25. HyDT113 and HyDT112 recorded the lowest concentrations of the group as these are further from the M25 than the other monitoring locations which are located around the perimeter of the AQMA. All other monitoring locations were observed to have concentrations greater than 40 µg/m³ for most years. 5.3.38 HMDT86 is on the perimeter of Hertsmere AQMA No.2 north east of junction 23 on the M25, This tube represents the nitrogen dioxide concentration at the boundary of the nearest property to the
M25. NO2 concentrations above 40 µg/m³.were recorded at this location for all years that data was available, 2008 to 2010 which is attributed mainly to road traffic emissions from the M25. 5.3.39 HMDT63 and HyDT183 are located on Dove Lane on the eastern perimeter of Hertsmere AQMA No.1 north of the M25 between Junction 23 and 24, and HyDT186, HyDT185 and HyDT184 are located in a transect of increasing distance from the M25 on Dove Lane outside of the AQMA. D7S1R1 represents the nearest property façade to the M25 at this location, which is a similar distance from the M25 to HMDT63 and HyDT183. HMDT63 recorded concentrations above 40 µg/m³ from 2006 to 2010, with similar concentrations being recorded at HyDT183. The concentrations reduce with distance from the M25. 5.3.40 HMDT43 is situated 32 m west of the Stirling Corner roundabout off the A411 Barnet Lane, in Borehamwood. The nearest relevant exposure is about 30 m across the A411. The relatively high concentrations at the site are likely to be due to the road traffic from the A411 approaching the roundabout and also the A1 Barnet By-pass dual carriageway. 5.3.41 HyDT246 and HyDT247 are located to the south east of the M25 Junction 25 within the Enfield whole borough AQMA. Both monitoring locations recorded concentrations above 40 µg/m³ in 2006 and 2008 and results for HyDT246 were also above 40 µg/m³ in 2007. The sites are quite some distance from the M25 (127 to 165m), and are predominantly influenced by the A10 south of junction 25.
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5.3.42 HyDT239 and HyDT240 are located to the south of the M25 close to the western exit portal of the Holmesdale Tunnel. The monitoring sites are located within Enfield whole borough AQMA and represent the residential properties adjacent to Holmesdale. Both monitoring locations are around 50 m from the M25, whereas the nearest receptor, D9S3R1, is only 25m from the M25. Both
monitoring locations recorded NO2 concentrations greater than 40 µg/m³ in 2006 and 2008 attributed to the relatively high background concentrations combined with local road traffic emissions. 5.3.43 BBDT10, HyDT226 and HyDT225 are all located north of the M25 around Broxbourne AQMA No.2 near to properties on Teresa Gardens close to the western entry portal of the Holmesdale Tunnel. The monitoring locations represent concentrations near to receptor D9S4R1, although the receptor is located slightly closer to the M25 than the monitoring locations. BBDT10 and HyDT226 recorded concentrations greater than 40 µg/m³ in 2006 and the results for HyDT226 and HyDT225 were greater than 40 µg/m³ in 2008 attributed to the high background concentrations and emissions from the M25. 5.3.44 BBDT11, EppDT383940, BBDT17 and HyDT231 are all located on Arlington Crescent around Broxbourne AQMA No.1, north of the M25 and close to the eastern exit portal of the Holmesdale Tunnel. HYDT231 is located closest to the M25 and represents the concentrations at the nearest receptor, D9S6R1 where emissions are attributed to the high background concentration and road
traffic emissions from the M25. NO2 concentrations were greater than 40 µg/m³ for all locations in all years where data was available 5.3.45 BBDT05 is located just 12 m to the south of the M25 opposite Broxbourne AQMA No.1, this tube is not representative of a sensitive receptor as it is much closer to the motorway than the nearest property represented by D9S5R1 on Hertford Road. There are only two years of data available for this location, which indicated concentrations greater than 40 µg/m³ in 2006 and 2008. 5.3.46 HyDT259 is located 55 m to the south of the M25 between Junction 25 and 26 in Epping Forest District Council. The monitoring site is located at a similar distance from the motorway to receptor D10S1R1 on Lodge Lane, Waltham Abbey. Concentrations greater than 40 µg/m³ were recorded in 2008 and are attributed to relatively high background concentrations and road-traffic emissions from the M25. 5.3.47 HyDT207 is located 65 m to the north of the M25 east of Junction 26 and is roadside to the A121 Honey Lane. The monitoring site is representative of receptor D10S3R1, The Lodge, Honey Lane. Concentrations above 40 µg/m³ were reported between 2006 and 2009 attributed to the relatively high background concentrations and road traffic emissions from the M25 and from Honey Lane. 5.3.48 EppDT313237 and EppDT36524 report the average values for two triple co-location sites between 40 and 60 m from the south of the M25 east of Junction 26. They represent concentrations at
receptor D10S4R1 and for most years concentrations were below 40 µg/m³, however in 2007 NO2 concentrations at EppDT313237 were equal to 40 µg/m³. 5.3.49 HyDT214 to HyDT223 and HyDT201 to HyDT203 comprise a group of 13 tubes surrounding Bell Common Tunnel between Junction 26 and 27 on the M25. HyDT218 to 220 are roadside to the B1393 High Road south of the western portal. HyDT222 is more associated with the local traffic conditions on the B1393 High Road and is not related to the M25. All other tubes are likely to be associated with M25 source contributions. All the tubes reported concentrations above 40 µg/m³ in 2008, seven were also above 40 µg/m³ in 2006 and eight were above 40 µg/m³ in 2007 and 2009. The only local authority tube in this area is EppDT2123 which only reported data in 2008 and found no concentrations above 40 µg/m³: this tube is located at the eastern extent of the area monitored. 5.3.50 BRWDT4 and BRWDT5 are both located within Brentwood AQMA No.2 which is associated with the Brook Street in Brentwood, the A12 and to an extent Junction 28 on the M25 (although this is some 96 to 113 m away, and so concentrations are likely to be mainly influenced by the other sources). Both tubes recorded concentrations above 40 µg/m³ between 2006 and 2009 with the
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highest concentrations recorded in 2008. Results at BRWTDT5 were also above 40 µg/m³ in 2010. 5.3.51 THDT9 is situated 55 m to the east of the M25. The site is near the façade of a residential property, which is within the Kemps Farm Cottage AQMA, off Dennis Road in South Ockendon. The property it at the end of a cul-de-sac and therefore high concentrations are due to road-traffic emissions on the M25. 5.3.52 In 2008, across the local air quality study area, DEFRA mapped background concentrations in the (ref. 5 21) grid squares where modelled receptors are located for NO2 and PM10 range between 14.2 and 25.8 µg/m³ and 16.6 and 21.8 µg/m³ respectively. Representative background concentrations
of NO2 and PM10 in 2008 are given in Appendix 5 in Volume 3, Table A5.3. 2008 NO2 concentrations from monitoring sites denoted as background sites between 200 metres and 1km of the ARN (diffusion tubes only) have been obtained to indicate the accuracy of the background
maps. Twelve such sites were available. The mapped total background NO2 concentrations were on average underestimating by 16% (with a range of 1% to 28% underestimation) compared to monitored concentrations. Defra mapped background concentrations are verified to within 30% of monitored concentrations at AURN background sites (ref 5.22). The comparison undertaken for the 12 identifed background sites concurs with this. Appendix 5 in Volume 3, Table A5.4 presents the comparison at the individual sites. Local Air Quality – Designated Sites 5.3.53 Local air quality conditions are also important in terms of sensitive nature conservation sites. Designated Sites may include particular features such as presence of various types of woodland, heathland, grassland, bog or sand dunes, which are sensitive to air pollution. Concentrations of pollutants in air and their consequent deposition can damage vegetation directly or affect plant health and productivity. 5.3.54 There are four Designated Sites within 200 m of the ARN, shown in Figure 5.1 and Figure 5.3. Three of these sites are sensitive to air pollution and are considered further in the assessment: Epping Forest SAC and SSSI unit 105 is located directly adjacent to the scheme between junctions 26 and 27 to the south of Bell Common Tunnel. Unit 201 of Epping Forest designated as SSSI lies adjacent to the M11 between junctions 6 and 7. Epping Forest SAC is primarily designated for its ancient semi-natural beech woodland, as well as old grassland plains and scattered wetland habitats, Unit 201 known as Gernon Bushes is described as lowland broad-leaved mixed and yew woodland with no specific species mentioned in the citation; Curtismill Green a SSSI consisting of unimproved grassland and scrub cited for its dry and wet grassland habitats is located on the south side of the M25 between junction 27 and 28. Only a small area of the SSSI is within 200 m of the M25, with the closest point around 150 m from the centreline of the M25 carriageway; Water End Swallow Holes, is a SSSI designated for its chalk sinkholes with ancillary willow carr and wet woodland community located around 60 m to the east of the A1(M) between junctions 1 and 2. Castle Lime Works Quarry is a SSSI located around 80 m to the west of the A1(M) between junctions 1 and 2, however as it is designated for geological reasons there are no air quality sensitive features on the site and it is not considered further in the assessment. 5.3.55 The UK‟s air pollution regulators and local planning authorities use an online tool called Air Pollution Information System (APIS) (ref 5.23) to evaluate the effects of air pollution on ecological habitats as part of their consenting or permitting work. The APIS website provides modelled data on nitrogen and acid deposition across the whole of the UK with a 5 km square grid resolution and site specific data for UK Designated SSSIs SACs and SPAs.
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5.3.56 The local air pollutants of relevance in the five designated sites are collectively referred to as
oxides of nitrogen (NOx). An EU Limit Value has been set for annual mean NOx concentration, known as the „Critical Level‟, for the protection of sensitive vegetation. Table 5.5 gives the relevant Critical Level defined by United Nations Economic Commission for Europe (UNECE) as: “concentrations of pollutants in the atmosphere above which direct adverse effects on receptors, plants, ecosystems or materials, may occur according to present knowledge.” (ref. 5.24)
Table 5.5 Critical Level for annual mean NOx for the protection of vegetation and ecosystems Pollutant Air Quality EU Critical Measured as … Date to be Objective Level achieved by (Limit Value)
NOx (expressed as NO2) 30 µg/m³ 30 µg/m³ Annual mean 31/12/2000
5.3.57 Relevant background concentrations for annual mean NOx and NO2 concentrations, taken from DEFRA‟s background mapping, are provided in Volume 3 Appendix 5, Table A5.10 to Table A5.13. These show the 1 km grid square data used to determine an average for the 5 km APIS squares for Epping Forest, Curtismill Green and Water End Swallow Holes. Table 5.6 presents the
background NOx concentrations used in the transect receptor modelling for 2008 and 2015 and the average NO2 background concentrations for 2008 and 2015 calculated for the 5 km grid square covering each of the Designated Sites,
5.3.58 The annual mean concentration of NO2 is relevant to the calculation of nitrogen deposition („N deposition‟) for which specific deposition rates have been set according to the sensitive habitats present at the sites. These are known as „Critical Loads‟ and are defined by the UNECE 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.” ref. 5.24)
Table 5.6: Estimates of site average background NO2 for determination of incremental dry N deposition rates in 2008 and 2015
Annual mean background Calculated average annual mean Transect Location NOx for transect receptors background NO2 for 5 km APIS square 2008 2015 2008 2015
31.7 20.1 Epping Forest – M25 17.2 12.1 28.7* 18.5* Epping Forest – M11 25.9 16.8 17.7 12.2 Curtismill Green 29.1 18.4 18.3 12.5 Water End Swallow Holes 25.7 16.8 19.0 13.1 * These represent background concentrations for the 1km background square with centrepoint 544500,201500 covering the three northern most points of Epping Forest transects 1, 2 &3. The rest of the designated site is represented by the 544500,200500 1km square.
5.3.59 N deposition relates to a number of substances in the atmosphere containing nitrogen but in terms
of pollution from transport sources relates mainly to emissions of NOx. 5.3.60 Table 5.7 gives the relevant Critical Loads for N deposition for the sensitive habitats at the three Designated Sites within the local air quality study area; these data have been obtained from the APIS website.
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5.3.61 Table 5.7 also presents the background N deposition values for the 5 km grid square enclosing each designated site reported on the APIS website as a 3 year average over the period 2006- 2008. In order to adjust this value to 2015 equivalent, as presented in the table below, the N deposition values given for 2006-2008 are assumed to represent the year 2007 and were reduced by 16% representing a linear reduction of 2% per year over 8 years in line with the methodology in HA207/07 Annex F Step 2. This adjustment accounts for expected reductions in deposition of reduced and oxidised nitrogen across Britain as a result of increasingly stringent emissions limits for road vehicles.
Table 5.7: Critical Loads for N deposition at designated sites within 200 metres of the ARN
Background N- Habitat (based on N deposition Grid reference of deposition for 5km Transect Name APIS designation Critical Load 5km APIS APIS square (kg text) Range square N/ha/year)
Epping Forest 35.0 (for 2007) 540000,200000 Fagus woodland 10 - 20 M25 Transects 29.4 (for 2015) Epping Forest Broadleaved deciduous 36.1 (for 2007) 545000,200000 10 - 20 M11 Transect woodland 30.3 (for 2015) Curtismill Green Low and medium 18.5 (for 2007) 550000,195000 20 - 30 Transect 1 altitude hay meadows 15.5 (for 2015) Water End Broadleaved deciduous 37.8 (for 2007) 520000,200000 10 - 20 Swallow Holes woodland 31.8 (for 2015)
5.3.62 Table 5.7 shows that background N deposition levels in 2007 and in 2015 exceed the critical load for Epping Forest and Water End Swallow Holes. For Curtismill Green the background N deposition levels are below the lower limit of the critical load. 5.4 Methodology General 5.4.1 DMRB HA207/07 (Ref 5.1) sets out the appropriate methodology for undertaking an air quality assessment for a Highways Agency scheme. Additional guidance is provided by DEFRA Local Air Quality Management (LAQM) technical guidance LAQM.TG(09) (ref. 5 25) and DfT‟s Transport Appraisal Guidance (WebTAG) (ref. 5.26). 5.4.2 The assessment is based on information and data from the following sources: geographical information from the Ordnance Survey; LAQM reports and monitoring data from South Buckinghamshire District Council, Chiltern District Council, Three Rivers District Council, Dacorum Borough Council, St Albans City and District Council, Welwyn Hatfield Borough Council, Hertsmere Borough Council, London Borough of Barnet, Broxbourne Borough Council, London Borough of Enfield, Epping Forest District Council, Harlow District Council, Uttlesford District Council, London Borough of Havering, Brentwood Borough Council and Thurrock Council; air quality monitoring data from the Highways Agency survey commissioned for the M25 scheme;
mapped estimates of background annual mean concentrations of NOx, NO2 and PM10 across the study area from DEFRA; background N deposition data from APIS;
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information on sensitive receptor locations from Ordnance Survey mapping, and on Designated Sites from Natural England; traffic data from Atkins‟ traffic modelling team based on output generated by the SATURN traffic model for the scheme; and scheme design and construction information and data provided by the Atkins and Skanska Balfour Beatty Joint Venture project teams. 5.4.3 The air quality assessment assumes: a base year of 2008; that the first full calendar year after opening is 2015 and this is the main assessment year for local air quality; and the design year is 2030 (relevant for the regional air quality assessment only). 5.4.4 In the case of the local air quality assessment the primary purpose of the 2008 base year is to enable comparison of modelled concentrations with appropriate, measured data from local monitoring so as to indicate model performance and allow model adjustment where justified. 5.4.5 For the assessment of regional emissions, the purpose of the 2008 base year is to set a baseline against which potential future year impacts can be compared. Local Air Quality Overview 5.4.6 The local air quality assessment methodology, as set out in the DMRB HA207/07, enables the potential effects of the scheme on concentrations of pollutants to be quantified. Conclusions can then be drawn on the significance of the overall effects of the scheme in terms of the local air quality on human health and Designated Sites sensitive to air pollution. 5.4.7 The DMRB HA207/07 provides a methodology for undertaking a Simple and/or Detailed level of assessment. For this Project, a Detailed level of assessment using an advanced air quality
dispersion model has been undertaken to determine the potential effects on NO2 and PM10 concentrations at selected sensitive receptors. The reasons for adopting a Detailed rather than Simple approach are in keeping with the DMRB HA207/07 guidance and include: the scheme involves changes to live carriageway areas that cannot be modelled by the Simple method; there are complexities in the study area environment that cannot be modelled by the Simple method such as complex junction arrangements, tunnel portals, relevant effects from grade separation and the need for use of realistic meteorological conditions; the current release of the Highways Agency‟s DMRB HA207/07 air quality screening model, incorporates factors that have been superseded. A Detailed approach allows use of more recent vehicle emission factors; and there are 21 AQMAs within the scheme local air quality study area.
5.4.8 Modelled estimates of annual mean road traffic-derived contributions to NOx and PM10 concentrations have been combined with annual mean background concentrations (i.e.
contributions from other sources), to calculate total concentrations of NO2 and PM10. 5.4.9 At locations that are relevant in terms of human exposure, modelled total concentrations are then compared to local air quality criteria (Table 5.1). This comparison is used to determine the nature of the local air quality impacts and to determine the significance of the overall effect of the scheme in 2015. The existing AQMA‟s (Table 5.2) are by definition considered to include particularly sensitive receptors, as they are locations of relevant exceedance. Receptors requiring due consideration will include those where there is likely to be relevant exposure, as defined in
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LAQM.TG(09); these will include residential premises, schools, and hospitals. Places of work and most pedestrian areas can generally be excluded where there is no relevant exposure over the relevant period.
5.4.10 For Designated Sites the estimated annual mean concentrations of NOx are compared to the Critical Level (Table 5.5). The estimated annual mean NO2 concentrations are converted to total N deposition for comparison with relevant Critical Loads (Table 5.7). ARN definition 5.4.11 The first step in the local air quality assessment is to identify the local air quality ARN so as to define the study area. The DMRB HA207/07 scoping criteria have been used for this purpose. The scoping criteria are change-based, where change is the difference made by the scheme to the opening year traffic data i.e. difference between the Do Minimum (DM) and Do Something (DS) scenarios. The criteria are: road alignment will change by 5 m or more; or daily traffic flows will change by 1,000 annual average daily traffic (AADT) flow or more; or Heavy Duty Vehicles (HDV) flows will change by 200 AADT or more; or daily average speeds will change by 10 km/hr or more; or peak hour speed will change by 20 km/hr or more. 5.4.12 The exercise to define the local air quality ARN has been undertaken in conjunction with the Atkins traffic modelling team, and only includes in the local air quality ARN those roads that are considered justified and relevant to the potential effect of the scheme. Where receptors are identified close to the local air quality ARN, then the detailed air quality model makes use of all relevant roads available from the traffic model within 200m of the receptor (i.e. not just the local air quality ARN). (For supplementary details relating to local ARN definition including a thematic map of the local air quality ARN, a table of data defining the local air quality ARN and the assumptions used, refer to Appendix 5 in Volume 3, Box A5.2.) Selection of receptors – human health 5.4.13 Receptors that are representative of worst-case locations by virtue of close proximity to the local
air quality ARN and in close proximity to measured annual mean NO2 concentrations that are above or close to the AQS objective and EU Limit Value threshold of 40 μg/m3 have been selected for assessment. 5.4.14 Appropriate receptors for human health have been identified using Ordnance Survey MasterMap® “Topography” and “Address Layer 2” data. The locations have been verified using aerial and street level photographs. Where receptors are buildings, the point at 1.5 m above ground level (as representative of breathing height) on the façade nearest to the local air quality ARN has been used for reporting of worst-case estimated pollutant concentrations. 5.4.15 Figure 5.2 in Volume 2 shows the locations of the receptors with respect to human health and Table A5.6 in Volume 3 gives details of the 77 illustrative receptors assessed. 5.4.16 To accommodate the study area (which includes much of the M25 between junctions 16 and 31 as well as parts of the A1, A10, A414, A1081 and the M11), and to account for variations in land use characteristics across the area and their influences on dispersion calculations, the study area was divided up into a number of model domains. Initially, 19 domains were defined; however, on closer examination using “Address Layer 2” datasets filtered to only include relevant exposure three of these (domains 8, 12 and 13) were discounted as having low risk of relevant exposure to significant effects in human health terms. Domain 8 has no locations with relevant exposure. Domain 12 has one relevant receptor, however this is sufficiently distant from the ARN that risk of significant effect is minimal. Domain 13 modelling was in relation to ecological impacts only (Curtismill Green SSSI). All 19 domains are listed below:
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Domain 1 - M25 from junction 17 northwards through junction 18 Chorleywood; Domain 2 - M25 from north of junction 18 though junction 19 Chandler‟s Cross; Domain 3 - M25 junction 20 northwards towards junction 21; Domain 4 - short section of the M25 between junctions 21a and 22, focussed on the A5183 Radlett Road where it crosses over the M25; Domain 5 - M25 between Shenley Lane, which is to the west of junction 22, through to the B566 Blackhorse Lane – to the east of junction 22; Domain 6 - M25 through South Mimms and junction 23; Domain 7 – M25 to the west of and including junction 24; Domain 8 (not modelled) – M25 between junctions 24 and 25; Domain 9 – M25 to the west of junction 25 to just to the east of Holmesdale Tunnel; Domain 10 – M25 from just to the east of Holmesdale Tunnel, through junction 26 to Crown Hill, Copped Hall Green; Domain 11 – M25 Bell Common Tunnel; Domain 12 (not modelled) – junction 27; Domain 13 (modelled for Designated Site only) – M25 section between junctions 27 and 28; Domain 14 – M25 junction 28 near Brentwood; Domain 15 – M25 between junctions 29 and 30; Domain 16 – M25 between junctions 16 and 17; Domain 17 – A414 and A1081 south of St. Albans; Domain 18 – A1(M) immediately north and south of the M25 between Apex Corner and Junction 3; and Domain 19 – M11 between junctions 5 and 8. Selection of receptors – Designated Sites 5.4.17 Lines of receptor points have been specified in the modelling extending to 200 m from the ARN within the Designated Sites; these points are termed „transect receptors‟. This has enabled
concentrations of total annual mean NOx and NO2 to be estimated for comparison with the Critical Level for NOx and, in the case of NO2, used in the calculation of N deposition within each site. Figure 5.3 shows the transect receptors within the sites that are assessed. Vehicle emissions 5.4.18 The dispersion model requires information on emission rates for each road link, in order to estimate traffic-derived pollutant concentrations. These emission rates are estimated from information on light and heavy duty vehicle flows and speeds. Heavy duty vehicles (HDV) are those exceeding 3.5 tonnes gross weight, including heavy goods vehicles and larger buses and coaches. Light Duty vehicles (LDV) are those below 3.5 tonnes gross weight excluding motorised two wheeled vehicles (ref 5.1).
5.4.19 Road traffic vehicle emission rates for NOx and PM10 have been calculated using the DEFRA‟s Emission Factor Toolkit (EFT) version 4.2.2 (November 2010) (ref. 5.27), which was the latest version at the time when the air quality assessment was undertaken. This method takes into account new, cleaner vehicle exhaust emissions standards Euro V (5) and VI (6) coming into service and replacement of older, more polluting vehicles according to forecasts included within the EFT
version 4.2.2. In the case of PM10 account is taken of particulate contributions from vehicle brake
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and tyre wear as well as from vehicle exhausts. Version 5.1 was released on 29th June 2012, but associated tools were not released at this time nor would the programme for the assessment allow use of this update. 5.4.20 Data on vehicle flows and speeds for each scenario have been provided by Atkins‟ traffic modelling team. These data, provided as hour by hour profiles showing the hourly variations in data with and without all lane running, are reflected in the emissions data that are used in the assessment. The data are based on traffic model estimates for average peak and inter-peak weekday hours with the use of profiles of observed hourly variations in traffic to generate values for night-time and weekend periods. The effect of delay due to congestion has been accounted for in traffic speed assumptions and the emissions are calculated for „congested speeds‟ rather than simply „cruise‟ or „free flow speeds‟, which would disregard congestion. Additional emissions due to peak hour queuing traffic has also been considered with examination of queue lengths generated from the SATURN traffic model output. (Traffic data are given in Volume 3, Appendix 5, Table A5.5). 5.4.21 The overall traffic changes expected with the scheme are increased flows from additional capacity on the mainline M25 motorway with improved journey times from reduced congestion, especially over peak periods. In addition there are increased flows on the A1081 and A414, between the M25 and M1 and the A1(M) and M11 to the north and south of the M25. No notable changes elsewhere in the local road network are expected, as shown by the extent of the local air quality ARN (refer to Appendix 5 in Volume 3, Box A5.2). Meteorological data 5.4.22 Detailed dispersion modelling takes into account local meteorological conditions, determined by using meteorological data from a representative weather station and specifying general land surface characteristics. Meteorological data from the London Heathrow Airport meteorological station have been used in the model. The station is approximately 28 km to the southwest of the scheme (from M25 junction 23). As there are no major topographical or coastal features in the area, the data are considered to be reasonably representative of the study area. (Further details of meteorological data and assumptions are given in Appendix 5, Volume 3, Box A5.3.) Determination of total concentrations 5.4.23 The ADMS Roads, version 3.1 (August 2011), atmospheric dispersion modelling system (ref. 5 28)
has been used to provide estimates of road contributions to annual mean NOx and PM10 concentrations. 5.4.24 The scheme extent includes two road tunnels at Waltham Cross (Holmesdale Tunnel between M25 junctions 25 and 26) and to the south of Epping (Bell Common Tunnel between M25 junctions 26 and 27), which are shown in Figure 5.1. As with the previous assessment at Stage 2, tunnel exit portal sources were represented as simple 100 m long volume sources, with the height and width of the volume equal to the dimensions of the tunnel portal opening. However, for Bell Common Tunnel (domain 11), a more sophisticated modelling system has been adopted after establishing that the representation of this relatively complex location using ADMS Roads was inadequate in this case. 5.4.25 Whilst ADMS Roads can be used to represent tunnel portal sources, only a very simplistic representation is possible by assuming a passive emission (i.e. without momentum) within a specified volume of air in front of the exit portal. Whilst this approach is generally accepted practice in the UK it does not always represent reality very well and can result in substantial under or overestimation of concentrations. In the case of Holmesdale tunnel (domain 9) it was found that the simplistic representation in ADMS Roads was acceptable, with monitored and model
estimated concentrations in terms of NO2 and PM10 comparing reasonably well (discussed in the following section on verification) thus giving confidence in the model. By contrast, at Bell Common
Tunnel, the pattern of concentrations for estimated NO2 did not agree very well with that from monitoring (there are no monitoring data for PM10 in this location) and so an alternative approach
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for the assessment of effects on NO2 was agreed with the Highways Agency for this location. The approach is in keeping with DMRB HA207/07 Annex E „Detailed Modelling‟ guidance.
5.4.26 For Bell Common Tunnel, modelling for NO2 used the GRAL (Graz Lagrangian) dispersion model system. The GRAL system has been developed by the University of Graz in Austria (ref. 5.29) and incorporates a dedicated tunnel portal source module. GRAL accounts for the horizontal jet-like emission of air forced from a tunnel exit portal by moving traffic and/or operating tunnel ventilation fans, its interaction with the ambient wind and other complex interactions that take place around tunnel portals. The model system (including the Graz Mesoscale Model – GRAMM) also generates localised wind field data by simulating the flow of air over the local terrain - including road cuttings - and other obstacles such as the entry portal canopies that were installed at Bell Common Tunnel by 2009. For the assessment, the simulation of air flow was based upon the same wind measurement data (plus other meteorological parameters) as the ADMS Roads model as well as high resolution digital terrain data held by Atkins. Like ADMS Roads, GRAL has been extensively validated and although not frequently used in the UK it is routinely used in Austria and other European countries for modelling dispersion from open road and tunnel portal sources in complex environments. A detailed modelling report, including technical information on the GRAL system and its validation is included in Volume 3, Appendix 6. 5.4.27 To derive estimates of total concentrations at receptors, model output data are combined with relevant background concentrations, as taken from DEFRA‟s background mapping (ref.5.21). These data are shown in Volume 3, Appendix 5, Table A5.3.
5.4.28 To transform annual mean road NOx concentrations into total NO2 concentrations, DEFRA‟s NOx to (ref 5 30) NO2 calculator has been used (calculations are provided in Appendix 5, Volume 3, Table A5.7). This requires input of the calculated road NOx at each receptor and a corresponding estimate of background annual mean NO2. The total annual mean NO2 concentrations that are produced by the calculator are directly comparable with the assessment criterion for annual mean 3. NO2 of 40 µg/m As only annual mean NO2 has been generated by this process, commentary on potential effects on hourly mean NO2 concentrations, which has its own criterion (Table 5.1) is possible with reference to LAQM.TG(09) guidance. This guidance suggest that if annual mean 3 concentrations of NO2 do not exceed 60 µg/m then it is unlikely that hourly mean concentrations would not meet the criterion set for the hourly mean.
5.4.29 To determine total annual mean concentrations of PM10 at human health receptors, the appropriate background concentration from DEFRA‟s background mapping (in Appendix 5, Volume 3, Table A5.3) have simply been added on to the model output. As only the annual mean
has been generated by this process, commentary on potential effects on 24-hour mean PM10 concentrations, which has its own criterion (Table 5.1) is possible with reference to LAQM.TG(09) guidance. This guidance gives an equation to estimate the number of days where the 24-hour mean criterion would be exceeded, with up to 35 exceedances being deemed acceptable: N = -18.5 + 0.00145a3 + (206 ÷ a) where „N‟ is the number of exceedances of the 24-hour mean threshold of 50 µg/m3 and „a‟ is
the total annual mean PM10 concentration.
5.4.30 For transect receptors in Designated Sites total annual mean NOx concentrations have been determined for comparison with the Critical Level (30 µg/m3) simply by adding the appropriate
background concentrations from DEFRA‟s background mapping to the annual mean road NOx concentration at receptors. Verification and adjustment of modelled estimated concentrations 5.4.31 Verification of base model outputs has been undertaken in accordance with the suggested methodology in LAQM.TG(09). Where adjustment is warranted, such as where systematic bias is clearly evident in the base year verification, adjustment is applied to bring modelled concentrations more into line with monitored concentrations. It is important to note, however, that there are limitations and uncertainties attached to all air quality modelling and as such reported
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total concentrations for receptors in future years will be indicative estimates, even after verification and adjustment, and should not be considered as definitive, guaranteed predictions, but are a reasonable and robust presentation of the results based on available information. 5.4.32 The available 2008 information for the monitoring sites within 200 m of the ARN (in Volume 3, Appendix 5, Table A5.1 and Table 5.4) was firstly reviewed to determine site suitability for use in
verification. Out of the 137 sites, 135 sites are NO2 diffusion tubes and provide direct measurement of NO2 only; however, not all are appropriate for verification purposes as many are not representative of nearby relevant exposure. Only one of the monitoring sites provides direct
measurements of NO2, NOx and PM10 (Arlington Crescent, Waltham Cross). Of the 137 sites, 86 were considered suitable for use in model verification (85 diffusion tubes for NO2, and one continuous analyser for NO2 and PM10). Details of the diffusion tube sites selected and those that were rejected are given in Appendix 5, Volume 3, Table A5.1.
5.4.33 For diffusion tube sites used in verification, which measure NO2 but not NOx, annual mean NOx concentrations have been calculated for comparison with modelled NOx concentrations. This has been undertaken using DEFRA‟s NO2 to NOx calculator (version 2.1), in accordance with LAQM.TG(09) guidance. 5.4.34 Volume 3, Appendix 5, Box A5.4 provides details of the verification and adjustments undertaken.
To address differences between modelled and monitored source NOx concentrations model setups were first revisited to ensure appropriate inputs. It was determined that an alternative to the ADMS Roads model for domain 11 was required. Having confirmed model inputs the verification as presented in Volume 3, Appendix 5, Box A5.4 was used to determine the need for adjustment, 5.4.35 Of the 85 verification sites (excluding 1 diffusion tube co-located with the CMS) the modelled
concentrations of annual mean NO2 at 65 sites were within ±25% of monitored concentrations, of these 32 were within ±10%. Of the 20 sites where the difference was greater than 25%, in all cases the model was found to overestimate the road contributed NOx component of „measured‟
NOx. One of the 20 sites (HyDT80) is particularly notable as the modelled NO2 has been overestimated by 109% (the maximum). Closer examination of this location shows that the M25 is elevated on a bridge relative to the diffusion tube, which is located only 11 m to the southeast of the anti-clockwise carriageway. An explanation for this overestimate is that the ADMS Roads representation at this location assumes no height difference between sources and receptors; consequently, the modelled concentration will be substantially overestimated.
5.4.36 Adjustment of the modelled source NOx component was considered necessary to bring the modelled concentrations more into line with monitoring (details are included in Volume 3, Appendix 5, Box A5.4). Following adjustment model performance was much improved with no
differences in modelled and monitored total annual mean NO2 greater than 25% and with 69 of the 85 comparisons within ±10%. This indication of model performance gives confidence to modelled values for 2015 scenarios.
5.4.37 Further details of model comparison and adjustment in relation to source NOx and total annual mean NO2 can be found in Volume 3 Appendix 5, Box A5.4. The model adjustment factors as applied to all local air quality receptors, including transect receptors in Designated Sites, are given in Volume 3 Appendix 5, Table A5.8.
5.4.38 For modelled concentrations of total annual mean NO2, there are sufficient data to generate statistics to indicate overall uncertainty in the adjusted model. The statistics include: the root mean square error („RMSE‟), which defines the average error or uncertainty in the model; the fractional bias („FB‟), which indicates systematic tendency of the model to over or under estimate concentrations; and the correlation coefficient („CC‟) used to indicate the linear relationship between monitored and modelled data. The statistics for the adjusted model are: RMSE = 2.8 µg/m3 (compared to 9.1 µg/m3 without adjustment) where the ideal value = 0.01 3 3 µg/m . The RMSE is less than 10% of the 40 µg/m Limit Value for annual mean NO2.
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Fractional bias = -0.001 (compared to -0.09 without adjustment), where a negative value indicates model over estimation. The value can range between +2 and -2 and the ideal value = 0 (i.e. no over or underestimation). Correlation coefficient = 0.9 (compared to 0.5 without adjustment), where a value of 1 indicates an absolute relationship and 0 indicates no relationship. 5.4.39 Only the Arlington Crescent continuous analyser site (Table 5.3) in model domain 9 provides data
for PM10 that can be compared with model concentrations. The comparison, which is presented in Table 5.8 below, shows good agreement for total concentrations, with the model slightly
overestimating. On this basis no adjustment of PM10 concentrations was undertaken. 3 Table 5.8: Comparison of modelled and monitored PM10 concentrations (µg/m ) Unadjusted Statistic Monitored Difference Modelled Source contributed annual mean 3 1.8 1.2 0.6 (µg/m ) Total annual mean (µg/m3) 22.6 22.0 0.6 (2.7%) Number of exceedances of 50 3 7 5 2 µg/m as the 24 hour mean (days) Notes: Background square 536500,200500 Background annual mean PM10 3 20.8 (µg/m )
5.4.40 Given the results presented above, and considering the examples of model verification and performance statistics given in Annex 3 of LAQM.TG(09), the adjusted model for local air quality
concentrations of annual mean NO2 can be judged to perform reasonably well, lending confidence to modelled concentrations for 2015.
Designated Sites
Estimation of NOx concentrations
5.4.41 No NOx monitoring data was available for locations within the designated sites so the modelled NOx concentrations at transect receptors were adjusted as described above for human health receptors. Adjusted NOx concentrations at the transect receptors for the base scenario and DM and DS in the opening year are compared to the Critical Level, given in Table 5.5. 5.4.42 To estimate the N deposition rates for the DM and DS scenarios in the opening year, the total
annual mean NO2 concentration at each transect receptors has been converted using the procedure described in DMRB HA207/07, Annex F. The road increment at each transect receptor
is the remainder when the average background NO2 values for the 5 km grid square, presented in Table 5.6 are removed from the modelled Total NO2 concentration at the receptor and adjusted to the Dry NO2 deposition rate by multiplying by 0.1. The total N deposition rate is the background N deposition rate presented in Table 5.7 plus the road increment. The calculated N deposition rates can then be compared with the Critical Loads for each of the Designated Sites (Table 5.7). 5.4.43 The implications for designated sites are considered separately to the air quality assessment, as part of the „Nature Conservation‟ topic.
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Regional Air Quality 5.4.44 DMRB HA207/07, paragraph 3.20(ref. 5.1), scoping criteria have been applied to define the regional ARN, which is different to that for local air quality. Roads were defined as affected if the comparison of modelled traffic data for DM 2015 with DS 2015 exceeded the following criteria: a change of more than 10% in AADT; or a change of more than 10% to the number of HDV; or a change in daily average speed of more than 20 km/hr. 5.4.45 Further details on the determination of the regional ARN are given in Volume 3, Appendix 5, Box A5.1. The assessment identified only 54 road sections that exceeded the criteria for AADT and/or HDV (traffic data for these road sections are given in Volume 3 Appendix 5, Table A5.9). Changes of more than 10% but involving less than ten vehicles were screened out of further calculations as in real terms the change in the number of vehicles is negligible. No links exhibited daily average speed changes exceeding 20 km/hr. 5.4.46 A regional air quality assessment was completed in accordance with DMRB HA207/07 to determine the pollutant emissions for the Regional ARN in the base (2008) scenario and DM and DS for opening year (2015) and design year (2030). The pollutants included in this assessment
are carbon, expressed as CO2 equivalent, NOx, particles and hydrocarbons. Emissions of carbon monoxide have not been calculated as this pollutant is no longer included in current vehicle emission factors (EFT version 4.2.2), which have been used in this assessment of regional emissions, as agree at the scoping stage. 5.4.47 The change in total emissions and distance travelled as a result of the scheme (i.e. DS) in the opening and design year are compared with the base and future year DM scenarios in Section 5.6. Construction Dust 5.4.48 As construction works will be taking place along the alignment within the Highways Agency‟s land boundary between M25 junctions 23 and 27, receptors within 200 m that may be affected by the works have been identified, as required by DMRB HA207/07. These receptors are shown in Figure 5.4. 5.4.49 Potentially sensitive receptors (e.g. residential properties, schools, medical facilities and Designated Sites) within 200 m of worksite areas have been identified. Since the exact foot print of the work sites is currently unknown, all receptors within 200 m of the scheme extent and adjacent Highways Agency land boundary have been highlighted. As the extent of physical works required for MM2 is relatively small (compared to conventional widening) this approach will be an overestimate of any impact. 5.4.50 The main purpose of the construction dust assessment is to highlight potentially sensitive receptors so that appropriate mitigation to minimise dust emissions can be rigorously applied at the time of construction. 5.4.51 Natural England had expressed concern about local roads within Epping Forest SAC experiencing significant increases in traffic during the construction period which might affect the more sensitive habitats found much further south of the M25 than the 200 m construction buffer. Planned construction of the scheme is minimal and disruption to normal traffic flow will be minimised with generally 3 lanes open to traffic during most works. Alternative routes will be signposted for drivers during significant disruption to normal flow on the M25 carriageway and none of these alternative routes will affect roads within Epping Forest SAC. Local drivers would still be able to use the roads which may result in a temporary increase in traffic on local roads; however there is not sufficient data to robustly predict these increases and hence the effect cannot be modelled in air quality terms to assess the resulting change in air pollution. Given the minimal disruption to
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traffic expected for MM2 there are unlikely to be significant transfers of traffic onto roads through Epping Forest SAC.
Definition of Significance of Effects Local air quality – human health 5.4.52 The Highways Agency position on local air quality (ref. 5.31) is: “On air quality, the Highways Agency is committed to delivering the most effective solutions to minimise the air quality impacts resulting from traffic using our network. We will operate and develop our network in a way that is compatible with working toward compliance with statutory air quality limits as part of our broader Environmental Strategy.” And “Where our road schemes are aimed at enabling our roads to carry greater volumes of traffic, we recognise that this can worsen air quality. When we assess that a scheme may worsen air quality we work to reduce or eliminate these adverse effects.” 5.4.53 The Highways Agency has advised that the approach for evaluating the significance of air quality effects is to be updated from the previous approach informally adopted by the HA. The previous approach considered whether there might be an overall worsening of air quality in relation to the EU Limit Values using an un-weighted change score. The score was calculated by identifying any and all receptors with an exceedance in the future year (either in the Do Minimum (DM) or Do Something (DS)), calculating the difference in concentrations with and without the scheme where there is such an exceedance, and summing the changes. 5.4.54 For the M25 Section 5 CALR scheme, the evaluation of the significance of air quality effects has been based on a working draft version of the proposed guidance („Review of the Highways Agency‟s Approach to Evaluating Significant Air Quality Effects‟, 7 September 2012)(ref. 5.32), and so the approach is outlined below. 5.4.55 The evaluation does not involve any additional modelling work than that already required, but uses
the verified/adjusted local air quality results for annual average NO2 (and where relevant for NOx) to describe the sensitivity, or capacity, for changes to air quality when compared with air quality thresholds, together with the extent, magnitude, probability and duration of the effect to inform a professional judgement of whether the effects of the project as a whole are considered to be significant. 5.4.56 The evaluation takes more account of the nature of the changes in opening year concentrations found by undertaking 6 tests, focused on locations with an exceedance either with or without the scheme. Each test question has the same weight. The test questions, and the metrics used to answer them, are shown in the table below. Table 5.9: Approach to evaluating the significance of air quality effects (opening year, annual average NO2) Ref. Evaluation Question Metric 1 Does the scheme result in For any receptors with concentrations above the relevant air a large change in quality threshold (results expressed to 1 decimal place) in either concentration above the the Do Minimum or Do Something, count the number of AQ threshold? receptors with a large change (Do Something – Do Minimum) of greater than or equal to 5% of the threshold. Count those with improvements or deteriorations such that: Worsen = XX receptors experience a deterioration of more than 5% of the relevant threshold Neutral = YY receptors experience a change of less than 5% of the relevant threshold Improve = ZZ receptors experience an improvement of more than 5% of the relevant threshold
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2 Does the scheme result in For receptors with concentrations over the relevant air quality an overall worsening or threshold (results expressed to 1 decimal place), in either the Do improvement in AQ above Minimum or Do Something scenario, calculate the sum total, the AQ threshold? maximum, arithmetic mean and frequency distribution (under the following ranges) of concentration changes to determine overall worsening or improvement. Improvements of more than 5% of the threshold Improvements of between 2.5% and 5% of the threshold Improvements of between 1% and 2.5% of the threshold Changes (both improvements and deteriorations) of less than 1% of the threshold Deteriorations of between 1% and 2.5% of the threshold Deteriorations of between 2.5% and 5% of the threshold Deteriorations of more than 5% of the threshold. 3 Does the scheme worsen For receptors with concentrations over the relevant air quality air quality for more threshold in either the Do Minimum or Do Something scenario receptors than it improves (using results rounded to zero decimal places), count the where air quality is already number of receptors predicted to experience a deterioration, poor? improvement or no change in air quality due to the scheme: Worsen = XX receptors above the thresholds experience a deterioration in air quality Neutral = YY receptors above the thresholds experience no change in air quality Improve = ZZ receptors above the thresholds experience an improvement in air quality 4 Does the scheme create For receptors with concentrations over the relevant air quality more exposure to poor AQ threshold in either the Do Minimum or Do Something scenario than it removes? (using results rounded to zero decimal places), count the number of receptors where the scheme impact is to create or remove an exceedance of the relevant air quality threshold (greater than, but not equal to), and those with no change in exceedance status: XX receptors experience a new exceedance of the threshold due to the scheme YY receptors experience a removal of an exceedance of the threshold ZZ receptors experience no change in exceedance of the threshold, but were already in exceedance 5 If new exceedances of the Where relevant, comment on whether these are clustered threshold occur as a result around existing exceedances (and therefore at least partially of the scheme, are they likely to be covered by existing AQAP measures) or whether adjacent to existing they are in new areas of exceedance and new AQAP measures exceedances or not? may be required: XX receptors experiencing a new exceedance are adjacent to existing areas of exceedance YY receptors experiencing a new exceedance are in new areas of exceedance Include comments on any existing AQAP relevant to each specific receptor with a new exceedance. 6 Does the scheme result in For receptors with concentrations over the relevant air quality a large delay in achieving threshold in either the Do Minimum or Do Something scenario the AQ threshold? (results expressed to 1 decimal place), calculate using current forecasting approaches, the estimated reversibility duration of the schemes impact and calculate frequency distribution of the reversibility durations in the following ranges: Less than 1 year 1-3 years (i.e. years 1 and 2 after opening) 3-5 years (i.e. years 3 to 5 after opening) 5+ years (i.e. after year 5)
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Note: For defining significance the Highways Agency has advised that an exceedance of the criterion 3 for annual average NO2 is defined as a concentration greater than 40.0µg/m .
5.4.57 The results of these indicators are then used, in the context of the total number of receptors considered in the assessment, to provide a professional judgement as to whether the impacts are considered to be significant and a commentary as to how that judgement was arrived at, based on the generic guidance from the EU on evaluating significance for the EIA Directive. 5.4.58 The assessment of significance takes no account of the actions of the HA or the local authority in addressing any underlying local air quality issue in the project study area: specifically in addressing any exceedances in the future Do Minimum. 5.4.59 If the evaluation concludes overall that the scheme impact is significant, then if mitigation measures are not already included for other reasons, these should be considered and the evaluation revisited. It is important to note that should any mitigation measures be developed to address the impact of the scheme, these only the address the change (the additional impact of the scheme over the opening year Do Minimum). Local air quality – Designated Sites 5.4.60 The DMRB HA207/07, paragraph 3.29 states that: “The NOx concentrations at the Designated Site(s) should be compared with the vegetation criterion for NOx and the change in concentration due to the project determined in the opening year. If the project is expected to cause an increase in concentrations of at least 2 µg/m³ and the predicted concentrations (including background) are very close to or exceed the criterion, then the sensitivity of that species to NOx should be commented upon”. (ref. 5.1) 5.4.61 These results are then used to provide a professional judgement as to whether the impacts are considered to be significant and a commentary as to how that judgement was arrived at, based on the generic guidance from the EU on evaluating significance for the EIA Directive. 5.4.62 The interpretation of significance of local air quality effects in terms of the Critical Level and Critical Loads at Designated Sites has been provided separately in Chapter 8 „Nature Conservation‟. Regional air quality 5.4.63 There are no criteria to define significance in terms of regional air quality effects; however, commentary on the expected changes in emissions brought about by the scheme has been provided in Section 5.7 below. Construction dust 5.4.64 The Highways Agency does not use criteria to define the significance of construction dust effects; however, it is recognised that construction dust effects may be adverse in-terms of increasing ambient concentrations of particulates and/or dust deposition and soiling rates, should they occur. 5.5 Regulatory/Policy Framework National Legislation and Policy
Local Air Quality - Human health 5.5.1 The means to protect public (human) health against poor ambient local air quality have been set out in national legislation. Part IV of the Environment Act 1995 (ref. 5 33) set out the principles of LAQM and requirements for the national AQS. 5.5.2 The current AQS was published in 2007 (ref. 5.2) and is intended to protect and improve ambient air quality in the United Kingdom in the medium-term, without imposing unacceptable economic or
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social costs. The strategy sets out health-based ambient air quality standards and objectives for
seven local air pollutants: carbon monoxide, benzene, 1,3-butadiene, lead, sulphur dioxide, NO2 and PM10. These are given statutory backing, in England, through the Air Quality (England) Regulations 2000 (ref. 5.34) and the Air Quality (England) (Amendment) Regulations 2002 (ref. 5.35). Of these seven pollutants the evidence base amassed through the LAQM process has demonstrated
that only NO2 and particulates (including PM10) remain of concern in relation to road traffic; this is because vehicle emissions of the other pollutants have declined so substantially that ambient concentrations are now well below AQS objective thresholds in all locations of routine public exposure near to roads. 5.5.3 Under the 1995 Act and in accordance with the AQS, local authorities are required to review their current and future air quality, and assess whether air quality standards and objectives are being achieved or are likely to be achieved. Local authorities are required to publicly report findings against a set programme set by DEFRA. The assessments have to be carried out in accordance with DEFRA LAQM policy and technical guidance LAQM.PG(09) (ref. 5.36) and LAQM.TG(09) respectively. 5.5.4 Where a local authority anticipates that an air quality objective would not be met, it is a requirement of the Act that an AQMA be declared. Where an AQMA is declared, the local authority is obliged to produce an Action Plan in pursuit of the achievement of the air quality
objectives. The majority of AQMA‟s in the UK are for NO2 due to emissions from road traffic, with some AQMA‟s associated with road traffic also designated for PM10. 5.5.5 UK regulations are largely governed by European legislation. The European Union (EU) Directive 2008/50/EC on ambient air quality and cleaner air for Europe sets Limit Values for pollutants. These Limit Values are included in UK legislation through the Air Quality Standards Regulations 2010 (ref. 5.37). Defra is responsible for compliance of zones and agglomerations on behalf of the UK Government. 5.5.6 The local air quality (human health) criteria that are relevant to this scheme assessment are given in Table 5.1. Local Air Quality – Designated Sites
5.5.7 The EU has set a Critical Level for annual mean NOx concentrations for the protection of vegetation in zones other than agglomerations. Directive 2008/50/EC (ref. 5.3) identifies that: “The risk posed by air pollution to vegetation and natural ecosystems is most important in places away from urban areas. The assessment of such risks and the compliance with critical levels for the protection of vegetation should therefore focus on places away from built-up areas.” 5.5.8 In England the critical levels have been incorporated into the Air Quality Standards Regulations
2010, Schedule 6. The Critical Level for NOx for the protection of vegetation is 30 µg/m³, as an annual mean. 5.5.9 The policy of the Statutory Nature Conservation Agencies‟ in the UK (in England, Natural England) 3 is to apply the 30 μg/m annual mean NOx Critical Level, at all locations on a precautionary basis, as a benchmark, in internationally designated conservation sites and SSSIs. Natural England highlighted tackling air pollution as one of their priority actions in their Biodiversity 2020 strategy, published in August 2011 (ref. 5.38). They aim to: “Reduce air pollution impacts on biodiversity through approaches at national, UK, EU and international levels targeted at the sectors which are the source of the relevant pollutants (nitrogen oxides, ozone, sulphur dioxide, ammonia)”.
5.5.10 In addition to the Critical Level for annual mean NOx concentrations, critical loads for nitrogen deposition have been set that represent (according to current knowledge) the exposure, below which there should be no significant harmful effects on sensitive elements of the ecosystem. These have been established for a number of habitats dependent on low nitrogen levels. Critical loads are expressed in deposition units of kilograms of nitrogen per hectare per year (kg N/ha/yr).
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Highways Agency 5.5.11 The Highways Agency position on local air quality (ref. 5.31) is: “On air quality, the Highways Agency is committed to delivering the most effective solutions to minimise the air quality impacts resulting from traffic using our network. We will operate and develop our network in a way that is compatible with working toward compliance with statutory air quality limits as part of our broader Environmental Strategy.” And “Where our road schemes are aimed at enabling our roads to carry greater volumes of traffic, we recognise that this can worsen air quality. When we assess that a scheme may worsen air quality we work to reduce or eliminate these adverse effects.” 5.5.12 In its Sustainable Development Plan 2012-2015 (ref. 5.39) the Highways Agency commits to managing carbon impacts in terms of its supply chain, estate, traffic officer and business related activities. The HA sets out to: "reduce greenhouse gas emissions by 25% from the whole estate and business-related transport" - against a 2010 baseline. 5.5.13 As part of continual improvement, the HA commits to building carbon management into lean processes and to consider resource impacts at design stages. 5.5.14 As an innovative measure regarding operational traffic the HA states its intention to: "Use intelligent transport systems to support the deployment and future exploitation of Managed Motorways, and contribute towards meeting carbon emission targets." National Planning Guidance 5.5.15 The planning guidance of general relevance for air quality is found within the National Planning Policy Framework (NPPF, March 2012) (ref 5.40), which replaces Planning Policy Statement (PPS) 23 Planning and Pollution Control and its Annexes. NPPF states that: 5.5.16 “Planning policies should sustain compliance with and contribute towards EU limit values or national objectives for pollutants, taking into account the presence of Air Quality Management Areas and the cumulative impacts on air quality from individual sites in local areas. Planning decisions should ensure that any new development in Air Quality Management Areas is consistent with the local air quality action plan.” Construction Dust – Statutory Nuisance 5.5.17 There are no statutory quantitative controls or limits on emissions of dust from a construction site however they are included in statutory nuisance provisions under the Environmental Protection Act 1990. Emissions resulting in levels at sensitive receptors which are substantially elevated above the norm can cause a statutory nuisance. This commonly relates to increased rates of dust deposition on exposed surfaces and / or soiling (discolouration / contamination), although less commonly the term may relate to levels that are “prejudicial to health”, including airborne dust. Detection of and requiring action to stop a statutory nuisance are responsibilities of the local authority. 5.5.18 In the context of the proposed development, dust emissions from demolition and construction works could result in a statutory nuisance if they were unreasonable to the average person and not properly controlled by the site. The defence against statutory nuisance is the use of “Best Practicable Means” (BPM) to control emissions. The application of BPM essentially means the managed, diligent application of “best practice” techniques to minimise emissions in the context of the receiving environment, changing conditions and cost. Regional Policy
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East of England 5.5.19 Under Part 1 of the Planning and Compulsory Purchase Act (2004) Regional Spatial Strategies have been prepared throughout England by the relevant regional planning body. In July 2010 the UK Government formally revoked Regional Spatial Strategies through the Local Democracy Economic Development and Construction Act 2009. However, a high court ruling determined that the Regional Spatial Strategies could not be abolished through this legislation and Regional Spatial Strategies have been reinstated for the time being. The Localism Bill was introduced in November 2011, which states that Regional Spatial Strategies will be abolished in the longer term once until new ways of addressing strategic planning and infrastructure issues are introduced. 5.5.20 The relevant Regional Spatial Strategy is the East of England Plan (ref. 5.41) covering the period 2001 to 2021. 5.5.21 Air Quality and emissions are specifically referred to under Policy T1: Regional Transport Strategy Objectives and Outcomes and Policy ENV7: Quality in the Built Environment of the East of England Development Plan. 5.5.22 Policy T1 refers to “improved air quality” and “reduced greenhouse gas emissions” as an outcome of managing travel behaviour and demand, encouraging efficient use of transport infrastructure, provision of infrastructure and transport services to support communities and improve access to jobs, services and leisure facilities. 5.5.23 Air quality is also referred to with respect to emissions under Policy ENV7 which states that “new development should reduce pollution, including emissions, noise and light pollution.” London 5.5.24 The London Plan (ref.5.42) is the overall spatial development strategy for Greater London. This sets out a fully integrated economic, environmental, transport and social framework for the development of London up to 2031. 5.5.25 Policy 7.14: Improving Air Quality states that “The Mayor recognises the importance of tackling air pollution and improving air quality to London‟s development and the health and well-being of its people. He will work with strategic partners to ensure that the spatial, climate change, transport and design policies of this plan support implementation of his Air Quality and Transport strategies to achieve reductions in pollutant emissions and minimise public exposure to pollution.” 5.5.26 The Mayor‟s Air Quality Strategy (ref.5.43) sets out specific policies and proposals to address the air quality issues, including reducing emissions from transport, reducing emissions from homes, business and industry and increasing awareness of air quality issues. The Mayor‟s Air Quality Strategy contains fourteen policies. Policy 1 to Policy 5 are aimed at reducing transport related air quality pollutants, Policy 6 to Policy 12 relate to non transport measures and includes a policy on reducing emission for construction and Policy 13 and Policy 14 relate to implementation of the Air Quality Strategy including working with the Government, other authorities and London Boroughs. The transport related measures proposed in the Mayor‟s Air Quality Strategy identified the need to work with the Highways Agency as “Part of the motorway network falls within the Greater London area and these roads are under the control of the Highways Agency” and “Reducing emissions from the M25, M4, M1 and M11 will help to improve London‟s air quality.” 5.5.27 With respect to construction Policy 6 related to reducing emissions from construction and demolition sites. London Councils and the GLA have published Best Practice Guidance „Control of dust and emissions from demolition and construction‟ (ref.5.44) which applies to construction projects within the GLA region. Buckinghamshire 5.5.28 Buckinghamshire‟s third Local Transport Plan 2011 – 2016 (ref.5.45) makes reference to air quality under the objective to “Reduce the negative impact of poor air quality,” where the aim is “for
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levels of air quality to be significantly improved in areas declared as AQMAs within Buckinghamshire”. The approach to achieving this includes delivering maintenance of walking and cycling routes, encouraging behavioural change, delivering management and tackling congestion, supporting new infrastructure and partnership working. 5.5.29 Air pollution is further considered within objectives to “Reduce the need to travel”, “Increase the proportion of people travelling by low emissions modes of transport” and the “Reduce carbon emissions and waste associated with the Transport Authority” objectives. Hertfordshire 5.5.30 Following introduction of the Local Development Framework development policy is largely up to the local authorities and is not co-ordinated through a central regional organisation. However a County wide Local Transport Plan and Air Quality Management Plan have been produced by Hertfordshire County Council. 5.5.31 Hertfordshire‟s third Local Transport Plan 2011 – 2031 (ref 5.46) makes reference to air quality under the goal to “Enhance quality of life, health and the natural, built and historic environment for all Hertfordshire residents,” where “…improving areas of poor air quality” is identified as a challenge. With reference to emissions there is a goal to “Reduce transport‟s contribution to greenhouse gas emissions and improve its resilience” where to “Reduce greenhouse gas emissions from transport” is stated as a challenge. 5.5.32 Air pollution is further considered within the policies where “The county council will seek to: A. Reduce the levels of emissions from road traffic which affect human health and local flora and fauna. B. Reduce the volume of traffic in areas and in time periods where emission levels are causing locally poor air quality. C. Encourage the through traffic to use the Primary Route Network where possible to avoid major urban areas. D. Work with District / Borough councils to monitor and assess air pollution levels. Where a District / Borough council declares an Air Quality Management Area as a result of its‟ review and assessment process, the county council will work in partnership with the District / Borough councils to create and deliver action plans.” 5.5.33 The LTP3 also states that “The county council also supports the following schemes proposed by DfT on motorways and trunk roads: Widening M25 Junctions 16-23 Motorway management M25 Junctions 23-27…” 5.5.34 The Hertfordshire Air Quality Management Plan (ref.5.47) (Hertfordshire County Council, 2009) sets out measures for improving air quality within the county, but none are related to motorways, where control of air pollution is the responsibility of the Highways Agency. Essex 5.5.35 Following introduction of the Local Development Framework development policy is largely up to the local authorities and is not co-ordinated through a central regional organisation although Essex County Council works closely with district and borough councils to ensure that their local development plans are in line with Essex County Council priorities. A County wide Local Transport Plan has been produced by Essex County Council. 5.5.36 Essex Transport Strategy (ref 5.48) is the third Local Transport Plan for Essex and identifies reducing carbon dioxide emissions and improving air quality through lifestyle changes, innovation and technology as a key outcome of the local transport plan, with challenges for: “a) Reducing the carbon-intensity of travel in Essex b) Reducing pollution from transport to improve air quality in urban areas and along key corridors c) Protecting enhancing the natural, built and historic environment” 5.5.37 These outcomes are supported by Policy 7: Carbon Reduction, where “Essex County Council will support and encourage the use of lower carbon travel” and Policy 9: The Natural, Historic and
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Built Environment, where “The County Council will protect the natural, historic and built environment from the harmful effects of transport by:” …” addressing air quality issues through appropriate measures, particularly in designated Air Quality Management Areas” Local Policy
5.5.38 Where a local authority has not yet adopted a Core Strategy under the Local Development Framework the following sections refer to the Local Plan documents that were a requirement prior to the introduction of The Planning and Compulsory Purchase Act 2004 in England and Wales (ref.5.49). South Buckinghamshire District Council 5.5.39 The South Bucks Local Development Framework Core Strategy (ref 5.50) was adopted in 2011. The document contains Core Policy 13: Environmental and Resource Management which states that the Council will seek to ensure the prudent and sustainable management of the District‟s environmental resources by “Seeking improvements in air quality, especially in the Air Quality Management area adjacent to the motorways”. 5.5.40 The council‟s air quality action plan (ref.5.51) sets out proposals for reducing pollution concentrations in AQMAs within the council area. The plan includes Actions 9, 10 and 11 which relate to emissions from the M25. Action 11 states that “The Council will continue to liaise with the Highways Agency to identify measures that can be taken to reduce nitrogen dioxide emissions associated with congestion on the M4, M40 and M25.” Chiltern District Council 5.5.41 The Chiltern District Local Development Framework Core Strategy (ref.5 52) was adopted in 2011. The document contains Policy CS26: Requirements of New Development which states that development proposals will be expected to “Ensure that all vehicular traffic generated by future development does not materially increase traffic problems, for example, congestion and local air quality”.
5.5.42 Chiltern District has declared one AQMA for exceedances of annual mean NO2 at an area in Chesham located over nine kilometres from the ARN. The Action Plan for the AQMA was published in October 2009 (ref 5.53) and states that the road providing the focus of the AQMA also forms part of a major through route („A‟ road) for vehicles travelling from the north to the southern motorways including the M25. Three Rivers District Council 5.5.43 The Three Rivers Core Strategy (ref.5.54) was adopted in 2011. This sets out the development plan to 2016 and beyond. Core Policy CP1: Overarching Policy on Sustainable Development identifies the need to reduce carbon emissions and manage and reduce the risk of and from air pollution. Widening of the M25 is identified as a strategic transport infrastructure project required to support the projected growth within the district. 5.5.44 The council have produced an air quality action plan (ref 5.55). The primary objective of the action
plan is to achieve AQS objective for NO2 with the AQMAs and. “Three Rivers District Council aims to encourage direct action upon the motorway (the Highways Agency has full control over the M25). The success of this element of the action plan is dependant on the Highways Agency commitment to reducing road traffic air pollution.” Dacorum Borough Council 5.5.45 Dacorum Borough Local Plan 1991 to 2011 (ref 5.56) was adopted in 2004. Policy 49: Transport Planning Strategy applies the principle “Road building, improvement and traffic management measures will only be permitted or supported where they meet safety, environmental or local access requirements. Schemes will not be promoted solely to provide additional capacity for
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private cars.” There is only a 500 metre section of the M25 at Junction 20 located with the boundaries of Dacorum Borough Council. On this basis the council does not have any policies which specifically mention the M25. 5.5.46 Dacorum Borough Council currently developing a Core Strategy which will set out policies to help achieve the vision of what the Borough should be like in 2031. This is expected to be adopted in by 2013 and will replace the Dacorum Borough Local Plan 1991 to 2011. 5.5.47 Dacorum Borough Council currently has no AQMAs and is not required to develop an air quality action plan. St Albans City and District Council 5.5.48 The District Local Plan Review (ref.5.57) contains no policies relevant to air quality. A policy regarding widening schemes on the M25 motorway was not retained when the plan was reviewed in 2007. The Council is currently in the final states of preparing a Core Strategy which will contain key planning policies and development proposals for the period 2011-2028. 5.5.49 The council‟s air quality action plan (ref.5.58) sets out proposals for reducing pollution concentrations in AQMAs within the council area. The plan states that, “St Albans Council anticipates encouraging and supporting the Highways Agency in taking actions that will result in a reduction in pollution levels from the M25 motorway. St Albans Council is currently working in co-ordination with Groundwork Herts and landowners along the M25 to establish the possibility of tree planting to create a tree barrier, however … the efficacy of a tree barrier and the benefits on the air quality in the AQMA are unknown.” Hertsmere Borough Council 5.5.50 The Hertsmere Local Plan (ref.5.59) was adopted in 2003 and sets out planning policy until 2011. It does not refer specifically to air quality or emissions from road schemes. Hertsmere Borough Council is currently consulting on its Core Strategy planning document which will out what development there should be, and where, in the borough until 2027. This document is expected to be adopted in 2012. 5.5.51 The Hertsmere Borough Council air quality action plan (ref.5.60) states that, “Hertsmere supports the Highways Agency in any means it identifies that will result in a reduction in pollution levels from traffic from both the M1 and M25 motorways and that it continues discussing the matter with the Highways Agency.” London Borough of Barnet 5.5.52 The Barnet Unitary Development Plan (ref.5 61) was adopted in 2006. Policy ENV7 – Air Pollution states “Development proposals that could lead to unacceptable levels of air pollution will not be permitted unless the developer is able to demonstrate that measures can be implemented that will mitigate these effects.” 5.5.53 The borough has produced an air quality action plan (ref 5.62). The primary aim of the action plan is
to improve air quality within the borough, currently declared as an AQMA for annual mean NO2 and 24 hour PM10. Action Points include “3. Make the Borough a Low Emission Zone (LEZ) for certain categories of vehicles by including the Borough in a London –wide LEZ” and “5. Improve traffic flow in general”. The conclusion at the London Borough of Barnet is that “measures taken at a local level are not sufficient...The Government policy makers should note this and consider as an urgent priority alternative ways of improving air quality.” London Borough of Enfield 5.5.54 The Enfield Plan - Core Strategy (ref.5.63) was adopted in 2010. The document sets out a spatial planning framework for the long term development of the Borough for the next 15 to 20 years. The document includes a number of strategic objectives which outline what will need to be
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achieved to deliver the Core Strategy vision and address the key issues that have been identified for the Borough. These strategic objectives are supported by core polices. 5.5.55 Core Policy 32: Pollution states that “The Council will work with its partners to minimise air, water, noise and light pollution and to address the risks arising from contaminated land and hazardous substances. In particular, new development will be required to: Improve air quality by reducing pollutant emissions and public exposure to pollution, particularly in areas identified as having poor air quality in the Air Quality Action Plan...” 5.5.56 Enfield‟s Air Quality Action Plan (ref.5.64) includes a chapter on transport planning and air quality. This Section specifically refers to the M25 and states that: “the Council will support the improvements to Junction 25 of the M25 provided they do not lead to an increase in road traffic.” Welwyn Hatfield Borough Council 5.5.57 The Welwyn Hatfield District Plan (ref 5.65) was adopted in 2005 and covers the period up to 2011. Policy R18: Air Quality states that, “the Council will have regard to the potential effects of a development on local air quality when determining planning applications. Consideration will be given to both the operational characteristics of the development and to the traffic generated by it. Any development within areas designated as AQMAs must have regard to guidelines for ensuring air quality is maintained at acceptable levels as set out in the AQS.” Welwyn Hatfield Borough Council is currently in the early stages of developing a Core Planning Strategy which will set the council's vision, objectives and delivery strategy for the development of the borough to 2026, and beyond. An expected adoption date has not yet been set. 5.5.58 Welwyn Hatfield Borough Council currently has no AQMAs and is not required to develop an air quality action plan. Broxbourne Borough Council 5.5.59 The Broxbourne Local Plan Second Review covers the period 2001-2011 and was adopted in 2005 (ref.5.66). Within the Broxbourne Local Plan Second Review Policy SUS5: Pollution states, “In considering proposals for potentially hazardous or polluting development, the council will assess the following: …The possible impact of the development on land use including the effects on health, the natural environment, or general amenity resulting from release to water, land or air, or of noise, dust, vibration, light or heat.” 5.5.60 The Broxbourne Local Plan will gradually be replaced by the Local Development Framework documents including the Broxbourne Core Strategy, a planning document which sets out a vision for the future of Broxbourne over the next 15 years. This document was expected to be adopted in 2012, however after pre-submission publication, the Inspector‟s Report in December 2011 concluded that the Core Strategy could be found sound only if a number of significant changes were made. Members of the Council are still considering their response. 5.5.61 In the Broxbourne Air Quality Action Plan (ref 5.67) Action 1 states that “The Council has no control over the M25 but will liaise with the Highways Agency to ensure that air quality in the borough is a consideration in the Environmental Impact Assessment for all relevant M25 projects.” Epping Forest District Council 5.5.62 The Epping Forest Combined Local Plan and Alterations (ref.5.68) 2008 includes Policy RP5A which relates to adverse environmental effects from development in terms of air quality and states that “The Council will not grant planning permission for …development where it could cause excessive … air … pollution for neighbouring land uses, protected wildlife species and habitats…except where it is possible to mitigate the adverse effects by the imposition of appropriate conditions.” Epping Forest District Council is currently in the early stages of developing a Core Planning Strategy which will set out the plans and policies that will guide development in Epping Forest district for the next 20 years. This is expected to be adopted in by 2014 and will replace the existing local plan.
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5.5.63 Epping Forest District Council currently has no AQMAs associated with the M25 but has declared an AQMA No.2 at Bell Vue, Bell Common and has not developed an air quality action plan at this point. Brentwood Borough Council 5.5.64 The Brentwood Replacement Local Plan (ref.5.69) provides a comprehensive statement of land use policies and proposals for the Borough up to 2011. Policy PC6 of the Brentwood Replacement Local Plan states that, “all new transport proposals and improvements to existing transport infrastructure and services will be assessed against their impact on air quality … and will need to be designed so as to minimise any negative impacts and, where necessary, incorporate reasonable and appropriate mitigation measures.” The M25 is identified as one of the main sources of poor air quality in the Borough. Brentwood Borough Council is currently developing the Brentwood Local Development Plan which will set out broad polices and proposals for shaping development in the Borough up to 2031. This will replace the 2005 Brentwood Replacement Local Plan and is expected to be adopted in 2013, 5.5.65 Brentwood Borough Council has produced an Air Quality Action Plan (ref.5.70) to try to reduce levels of pollution within the council area. This plan identifies the Highways Agency as the responsible organisation for actions related to air pollution associated with the M25. London Borough of Havering 5.5.66 The London Borough of Havering adopted a Core Strategy and Development Control Policies Development Plan Document (ref.5.71) in 2008 which sets the Council‟s approach to the planning of the whole borough up to 2020. Core Policy CP15: Environmental Management, requires that new developments do not singularly or cumulatively breach air quality targets. In the absence of any specific local targets, this is deemed to refer to national air quality objectives. Development Control Policy DC52: Air Quality states that “Planning permission will only be granted where new development, both singularly or cumulatively, does not cause significant harm to air quality, and does not cause a breach of the targets set in Havering's Air Quality Management Area Action Plan. A formal assessment will be required where it is suspected that a development is likely to cause a breach of emission levels for prescribed pollutants. Where the assessment confirms a breach, planning permission will only be granted if suitable mitigation measures are put in place through conditions or legal agreement.” Thurrock Council 5.5.67 The Thurrock Transport Strategy 2008 – 2021 (ref.5.72) establishes the way in which congestion, road safety, air quality and enabling better access to services will be tackled in Thurrock. It sets out how transport improvements will be delivered between 2008 and 2021. 5.5.68 The Thurrock Local Development Framework Core Strategy (ref.5.73) was adopted in 2011. CSTP14 – Transport in the Thurrock Urban Area includes several measures with the aim of delivering a 10% reduction in car traffic from forecast 2026 levels. 5.5.69 The Thurrock Council air quality action plan (ref.5.74) Action 2 states that, “The Council will liaise with the Highways Agency to ensure that air quality in the Borough is a consideration in the Environmental Impact Assessment for all relevant strategic road projects.” Harlow District Council 5.5.70 The Replacement Harlow Local Plan was adopted in July 2006 (ref.5.75). The Local Plan contained Policy BE18 related to air pollution, stating: “Planning permission will be granted if a development does not have the potential to contribute to significant levels of air pollution or is not sensitive to the effect of existing sources of air pollution or if adequate provision is made to mitigate against adverse effects on air quality”. However, this policy expired as it was not part of the saved policies in the Secretary of State's Direction dated May 2009.
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5.5.71 Harlow District Council is currently developing a Core Strategy which will set out the detailed planning policies and proposals that will shape the future of Harlow. Consultation is anticipated by autumn 2012 before submission to Government for formal examination. 5.5.72 Harlow District Council currently has no AQMAs and is not required to develop an air quality action plan. Uttlesford District Council 5.5.73 The Uttlesford Local Plan (ref.5.76) was adopted in 2005. Policy ENV12 – Exposure to Poor Air Quality states “Development that would involve users being exposed on an extended long-term basis to poor air quality outdoors near ground level will not be permitted. A zone 100 metres on either side of the central reservation of the M11 and a zone 35 metres either side of the centre of the new A120 have been identified on the proposals map as particular areas to which this policy applies”.
5.5.74 Uttlesford District has declared three AQMA for exceedances of annual mean NO2 at three streets in Saffron Walden, located over 11 kilometres from the ARN. The Action Plan for these AQMAs was published in 2009 and does not mention the M25. 5.6 Design, Mitigation and Enhancement Measures Local and Regional Air Quality 5.6.1 Detailed modelling of local air quality impacts (human health) and use of the Highways Agency method for evaluating significance has demonstrated that mitigation would not be required. 5.6.2 No mitigation of regional emissions is included. Construction Dust 5.6.3 To mitigate potential construction dust effects the contractor should ensure that use of Best Practicable Means (BPM), as defined in the Environmental Protection Act 1990 (ref. 5.72), can be demonstrated in the day to day prevention and control of dust emissions from the works. The level of mitigation implemented should take into account: the nature and duration of the works; proximity of sensitive receptors; and changing weather and ground conditions. 5.6.4 Typical measures may include: restriction of vehicle speeds to no more than 15 mph when on site to minimise dust mobilisation due to the passage of vehicles; regular cleansing of pavement surfaces using appropriate means, such as vacuum sweeping to minimise the accumulation of material that may be picked up by the wind or passing vehicles; minimisation of materials handling activities; minimisation of material drop heights; rapid stabilisation of top soil storage mounds; store potentially dusty materials in enclosed areas and away from potentially sensitive receptors; use of wet suppression or air extraction systems when cutting, drilling or grinding to prevent dust emissions; prohibit burning; sheeting or containment of loads of potentially dusty materials transported to and from work site areas via the live public highway; and
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provision of wheel and chassis cleansing facilities to remove accumulations of mud from vehicles prior to driving on the live public highway. 5.6.5 Measures should be incorporated into the Construction Environmental Management Plan (CEMP) for the scheme, reflecting the requirements of BPM. Regular visual inspection and record keeping describing ongoing works, conditions and mitigation is recommended as part of routine site environmental management. 5.7 Magnitude of Impacts (Change) Local Air Quality Effects Human health 5.7.1 The effects on local air quality in terms of human health have been estimated following the method described in Section 5.3 above. Modelled concentrations have been provided for the base year (2008) and with (DS) and without (DM) the scheme in the opening year 2015. Estimates have been made at 77 receptors that are representative of worst-placed locations due to their close proximity to the ARN. 5.7.2 The verified and adjusted modelled concentrations are presented in Table 5.10 for annual mean
NO2 and Table 5.11 for annual mean and daily mean PM10.
Table 5.10: NO2 concentrations and changes with the scheme Annual mean concentrations (µg/m3) (AQS objective/Limit Value = 40 µg/m3) Receptor ID 2008 Base 2015 DM 2015 DS DS - DM
D1S1R1 52.6 36.2 36.3 0.1 D1S2R1 34.0 22.2 22.2 0.0 D1S3R1 29.2 18.7 18.8 0.1 D1S4R1 40.3 26.1 26.2 0.1 D1S5R1 41.4 26.9 26.9 0.0 D1S6R1 38.9 24.9 25.0 0.1 D1S7R1 41.2 27.6 27.7 0.1 D2S1R1 36.5 23.4 23.4 0.0 D2S2R1 32.6 21.0 21.1 0.1 D2S3R1 41.9 28.6 28.7 0.1 D3S1R1 38.4 24.5 24.6 0.1 D3S2R1 35.7 22.9 23.0 0.1 D3S3R1 34.5 22.4 22.4 0.0 D3S4R1 29.7 19.6 19.6 0.0 D3S5R1 49.4 33.7 33.9 0.2 D3S6R1 48.0 32.1 32.3 0.2 D4S1R1 44.3 29.3 29.6 0.3 D4S2R1 42.2 27.8 28.2 0.4 D5S1R1 49.6 33.1 33.7 0.6 D5S2R1 41.8 27.3 27.7 0.4 D5S3R1 49.7 33.6 34.3 0.7 D6S1R1 43.8 29.4 29.9 0.5 D6S2R1 54.3 38.1 39.0 0.9 D6S3R1 46.1 30.6 31.2 0.6
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Annual mean concentrations (µg/m3) (AQS objective/Limit Value = 40 µg/m3) Receptor ID 2008 Base 2015 DM 2015 DS DS - DM
D6S4R1 47.3 31.0 32.1 1.1 D7S1R1 55.8 37.3 39.3 2.0 D9S1R1 33.8 21.7 22.2 0.5 D9S2R1 59.4 39.5 40.5 1.0 D9S3R1 53.9 36.2 37.4 1.2 D9S4R1 47.1 31.1 32.0 0.9 D9S5R1 42.2 27.4 28.0 0.6 D9S6R1 53.6 35.9 37.2 1.3 D10S1R1 45.9 30.6 31.9 1.3 D10S2R1 43.1 28.2 29.3 1.1 D10S3R1 49.0 32.9 34.0 1.1 D10S4R1 36.8 24.3 25.0 0.7 D10S5R1 38.0 24.3 24.9 0.6 D10S6R1 36.5 23.5 24.1 0.6 D11S1R1 54.0 38.3 40.6 2.3 D11S2R1 36.9 21.3 22.1 0.8 D11S3R1 46.9 28.5 29.8 1.3 D11S4R1 42.6 26.1 27.3 1.2 D14S1R1 55.3 37.6 37.9 0.3 D14S2R1 37.2 24.3 24.4 0.1 D14S2R2 29.0 18.8 18.9 0.1 D15R1 37.3 24.4 24.5 0.1 D15R2 35.8 23.1 23.2 0.1 D15R3 33.8 21.8 21.9 0.1 D15R4 32.3 21.6 21.6 0.1 D15R5 33.0 21.2 21.3 0.1 D16R1 50.8 35.3 35.4 0.1 D16R2 55.2 39.1 39.2 0.1 D16R3 44.9 29.1 29.2 0.0 D16R4 28.1 18.2 18.2 0.0 D16R5 38.0 25.2 25.3 0.1 D16R6 35.8 23.8 23.9 0.1 D16R7 34.7 23.2 23.3 0.1 D16R8 32.3 21.1 21.1 0.0 D17R1 33.6 22.1 22.3 0.2 D17R2 31.4 20.5 20.7 0.2 D18R1 33.2 21.0 21.1 0.1 D18R2 29.2 18.5 18.6 0.1 D18R3 32.1 20.4 20.5 0.1 D18R4 27.1 17.9 18.0 0.1 D18R5 28.0 18.3 18.3 0.0 D18R6 28.3 17.9 18.0 0.1 D18R7 26.6 17.0 17.0 0.0 D19R1 37.4 23.7 23.8 0.1
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Annual mean concentrations (µg/m3) (AQS objective/Limit Value = 40 µg/m3) Receptor ID 2008 Base 2015 DM 2015 DS DS - DM
D19R2 37.6 23.8 23.9 0.1 D19R3 33.4 21.2 21.4 0.2 D19R4 36.3 23.0 23.1 0.1 D19R5 35.5 22.6 22.7 0.1 D19R6 26.0 16.5 16.5 0.0 D19R7 32.2 20.1 20.2 0.1 D19R8 31.0 19.6 19.7 0.1 D19R9 29.4 18.5 18.6 0.1 D19R10 27.3 17.2 17.2 0.0 Notes: Values in bold indicate exceedances of the 40 µg/m³ AQS objective for annual mean NO2.
5.7.3 The changes in annual mean NO2 due to the scheme in 2015 can be summarised as: Increases greater than or equal to 1 µg/m3 at 11 out of 77 receptors, with a maximum increase of 2.3 µg/m3 at D11S1R1, which is to the west of Bell Common tunnel (Figure 5.2) Increases greater than or equal to 0.4 (at least) and less than 1 µg/m3 at 15 receptors out of 77 Increases of less than 0.4 µg/m3 at 51 receptors out of 77 No reductions in concentration with the scheme 3 5.7.4 Two new exceedances of the 40 µg/m criterion for annual mean NO2 are indicated with the scheme in 2015, whilst DS concentrations at all other receptors would remain below this threshold. The new exceedances would be at D9S2R1 and D11S1R1. The change at D9S2R1 from the DM concentration of 39.5 µg/m3 is an increase of 1.0 µg/m3 to 40.5 µg/m3. At D11S1R1 the change would be an increase of 2.3 µg/m3 from the DM concentration of 38.3 µg/m3 to the DS concentration of 40.6 µg/m3. 5.7.5 Receptor D9S2R1 is adjacent to the A10, to the south of M25 junction 25; it is within the London
Borough of Enfield‟s Enfield AQMA for annual mean NO2 (and 24 hour PM10). Modelled source apportionment indicates that the A10 and other non-HA roads account for 68% of the total annual 3 mean road NOx at this receptor, with M25 sources contributing 32%. The increase of 1.0 µg/m in annual mean NO2 in 2015 with the scheme can be attributed to the attraction of traffic to the M25, as shown by increases in AADT flows on the M25 between junctions 24 and 25 of 19,786 and between junctions 25 and 26 of 17,503 over the DM (Appendix 5 Box A5.2). 5.7.6 Receptor D11S1R1 is on the western side of Bell Common Tunnel to the south of the M25. It is 3 the physically the closest receptor in the vicinity. The increase of 2.3 µg/m in annual mean NO2 in 2015 with the scheme can be attributed to the attraction of traffic to the M25, as shown by an increase in AADT flows on the M25 between junctions 26 and 27 of 15,615 over the DM. The increase with the scheme is more pronounced at this receptor than at D9S2R1 (which has a larger increase in traffic) because of its closer proximity to the M25 sources. 5.7.7 In general, the increases in concentrations at other receptors between M25 junctions 23 and 27 with the scheme are the most pronounced across the wider study area, and are primarily a result increases in traffic flows on the M25 and also the shift in carriageway centrelines to be slightly closer to receptors due to full time utilisation of the hard shoulders as running lanes. Beyond the scheme limits the increases experienced at receptors are solely due to increases in traffic flows, with effects lessening with distance from the scheme.
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3 5.7.8 As annual mean NO2 concentrations are below 60 µg/m , it is unlikely that the criterion for hourly mean concentrations would be exceeded, according to LAQM.TG(09) guidance.
Table 5.11: PM10 concentrations and changes with the scheme Annual mean concentrations Number of days exceeding 24 hour 3 3 (µg/m ) mean of 50 µg/m PM10 Receptor (AQS objective/Limit Value = 40 (AQS objective/Limit Value allows up 3 ID µg/m ) to 35 exceedances) 2008 2015 2015 DS - 2008 2015 2015 DS - Base DM DS DM Base DM DS DM D1S1R1 20.9 18.4 18.5 0.1 5 2 2 0 D1S2R1 20.6 18.1 18.2 0.1 4 2 2 0 D1S3R1 20.3 18.1 18.1 0.0 4 1 1 0 D1S4R1 21.6 18.6 18.6 0.0 6 2 2 0 D1S5R1 21.3 18.9 18.9 0.0 5 2 2 0 D1S6R1 21.5 18.8 18.9 0.1 6 2 2 0 D1S7R1 23.4 20.5 20.5 0.0 9 4 4 0 D2S1R1 19.3 17.5 17.5 0.0 3 1 1 0 D2S2R1 21.3 19.2 19.2 0.0 5 3 3 0 D2S3R1 23.2 20.2 20.2 0.0 9 4 4 0 D3S1R1 21.0 19.0 19.0 0.0 5 2 2 0 D3S2R1 21.6 19.2 19.2 0.0 6 2 2 0 D3S3R1 22.0 19.8 19.8 0.0 6 3 3 0 D3S4R1 22.3 19.3 19.4 0.1 7 3 3 0 D3S5R1 22.9 20.4 20.4 0.0 8 4 4 0 D3S6R1 21.7 19.4 19.4 0.0 6 3 3 0 D4S1R1 22.9 20.0 20.1 0.1 8 3 3 0 D4S2R1 22.7 19.9 19.9 0.0 8 3 3 0 D5S1R1 22.2 19.7 19.7 0.0 7 3 3 0 D5S2R1 21.9 19.3 19.3 0.0 6 3 3 0 D5S3R1 23.8 21.1 21.1 0.0 10 5 5 0 D6S1R1 23.2 20.4 20.4 0.0 9 4 4 0 D6S2R1 24.7 21.3 21.4 0.1 12 5 5 0 D6S3R1 21.4 19.3 19.3 0.0 5 3 3 0 D6S4R1 23.5 20.6 20.7 0.1 9 4 4 0 D7S1R1 23.3 20.3 20.4 0.1 9 4 4 0 D9S1R1 20.8 18.7 18.8 0.1 4 2 2 0 D9S2R1 22.9 20.2 20.3 0.1 8 4 4 0 D9S3R1 22.4 19.6 19.7 0.1 7 3 3 0 D9S4R1 22.5 20.0 20.1 0.1 7 3 3 0 D9S5R1 22.6 20.3 20.3 0.0 7 4 4 0 D9S6R1 23.4 20.4 20.5 0.1 9 4 4 0 D10S1R1 22.5 20.9 21.0 0.1 7 5 5 0 D10S2R1 21.8 20.2 20.3 0.1 6 4 4 0 D10S3R1 22.2 20.6 20.7 0.1 7 4 4 0 D10S4R1 22.2 20.7 20.8 0.1 7 4 5 1 D10S5R1 21.2 19.7 19.8 0.1 5 3 3 0 D10S6R1 20.8 19.4 19.4 0.0 4 3 3 0 D11S1R1 21.6 19.6 19.8 0.2 6 3 3 0
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Annual mean concentrations Number of days exceeding 24 hour 3 3 (µg/m ) mean of 50 µg/m PM10 Receptor (AQS objective/Limit Value = 40 (AQS objective/Limit Value allows up 3 ID µg/m ) to 35 exceedances) 2008 2015 2015 DS - 2008 2015 2015 DS - Base DM DS DM Base DM DS DM D11S2R1 22.0 20.2 20.3 0.1 6 4 4 0 D11S3R1 22.0 20.2 20.2 0.0 6 4 4 0 D11S4R1 24.0 21.3 21.4 0.1 10 5 5 0 D14S1R1 24.1 21.0 21.0 0.0 10 5 5 0 D14S2R1 23.5 20.9 20.9 0.0 9 5 5 0 D14S2R2 22.5 20.4 20.4 0.0 7 4 4 0 D15R1 23.7 21.1 21.1 0.0 10 5 5 0 D15R2 22.7 20.3 20.3 0.0 8 4 4 0 D15R3 22.5 20.2 20.2 0.0 7 4 4 0 D15R4 21.9 19.8 19.8 0.0 6 3 3 0 D15R5 22.3 20.1 20.1 0.0 7 4 4 0 D16R1 22.8 19.8 19.9 0.1 8 3 3 0 D16R2 23.6 20.4 20.4 0.0 9 4 4 0 D16R3 22.0 19.2 19.2 0.0 6 2 2 0 D16R4 20.0 18.2 18.2 0.0 3 2 2 0 D16R5 22.2 19.9 19.9 0.0 7 3 3 0 D16R6 20.7 18.5 18.5 0.0 4 2 2 0 D16R7 20.7 18.6 18.6 0.0 4 2 2 0 D16R8 20.4 18.3 18.3 0.0 4 2 2 0 D17R1 19.5 17.6 17.6 0.0 3 1 1 0 D17R2 19.6 17.7 17.7 0.0 3 1 1 0 D18R1 21.2 18.9 18.9 0.0 5 2 2 0 D18R2 20.7 18.6 18.6 0.0 4 2 2 0 D18R3 21.8 19.6 19.6 0.0 6 3 3 0 D18R4 19.3 17.4 17.4 0.0 3 1 1 0 D18R5 19.5 17.6 17.6 0.0 3 1 1 0 D18R6 20.6 18.6 18.6 0.0 4 2 2 0 D18R7 20.4 18.4 18.5 0.1 4 2 2 0 D19R1 23.9 21.4 21.4 0.0 10 5 5 0 D19R2 23.9 21.4 21.5 0.1 10 5 5 0 D19R3 22.0 19.9 19.9 0.0 6 3 3 0 D19R4 22.4 20.1 20.1 0.0 7 3 3 0 D19R5 23.2 20.9 20.9 0.0 9 5 5 0 D19R6 20.8 19.0 19.0 0.0 5 2 2 0 D19R7 22.2 20.0 20.0 0.0 7 3 3 0 D19R8 21.6 19.5 19.5 0.0 6 3 3 0 D19R9 23.3 21.2 21.2 0.0 9 5 5 0 D19R10 22.4 20.5 20.5 0.0 7 4 4 0
5.7.9 In terms of annual mean PM10 concentrations, the changes can be summarised as: No increase of 0.5 µg/m3 or more at any receptor Increases of less than 0.5 µg/m3 at 77 receptors
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5.7.15 Exceedances are found at Junction 25 with the A10, and between Junction 26 and 27 at Bell Common Tunnel in locations from south of Junction 16 to Junction 28. Over half of these locations (19) are outside the scheme extent, in the wider local air quality ARN. Within the scheme extent, 13 locations exceed and are made worse by the scheme. 5.7.16 The following paragraphs address each question in turn. 5.7.17 Question 1 shows that of the two receptors with an exceedance only one has a „large‟ change: at M25 J26-27 Bell Common Tunnel, receptor D11S1R1 Yew Tree Cottages, immediately south- west of the western exit portal. This receptor is not indicative of a wider area of exceedance as there is only one other receptor nearby (Park Cottages), which has been assessed and does not exceed, with or without the scheme. 5.7.18 Question 2 is a variant of the change score previously used by the Highways Agency for determining significance. A positive score of 3.3 suggests some negative impact from the scheme, although a simple summation is influenced by the number of receptors assessed. The maximum change of 2.3 µg/m3 occurs at D11S1R1 Yew Tree Cottages (as identified in question 1). 5.7.19 For question 2, the bands show the frequency distribution of changes in concentrations at exceedance locations. One receptor has a worsening of over 5% of the threshold (a large change), at D11S1R1. No receptors have an improvement with the scheme.. 5.7.20 Questions 3 and 4 simply reflect that two receptors have new exceedances with the scheme as outlined earlier. 5.7.21 For Question 5, of the two new exceedances, one is associated with a wider area of existing exceedances. This is receptor D9S2R1 which is adjacent to junction 25 between the A10/M25.
This is within the Enfield AQMA, a whole borough declaration for annual average NO2 (and 24hr mean PM10).There is an AQAP (air quality action plan) for this AQMA, although there are no specific measures for this specific location. 5.7.22 Question 6 shows that receptors would need 1 to 3 years to resolve the additional poor air quality from the scheme relying on national measures being rolled out anyway, without any local action. In practice both receptors would only need 1 year after opening. 5.7.23 It is important to note that modelling results used in the significance evaluation do not include any mitigation applied. This should not be taken as implying that mitigation measures are not available to address any worsening arising from the scheme. 5.7.24 Taking these results and applying the EU guidance on judging significance results in 11 of the 17 standard questions which remain relevant for putting such findings in context. These are shown in the Table 5.13 below. Table 5.13: EU Criteria for Evaluating Significance – M25 Section 5 Local Air Quality (annual average NO2) Ref. EU Criteria Determination 1 Will there be a large change in No. There is only one qualifying receptor with an increase environmental conditions? greater than 2 µg/m3 with the scheme (1% of those assessed).
2 Will new features be out-of- Not relevant for local air quality. No new road sources are scale with the existing introduced with the scheme, with impacts reflecting the environment? increased use of an existing road. 3 Will the effect be unusual in the Not for annual average NO2 concentrations, as all receptors area or particularly complex? assessed show an increase in concentrations with the scheme.
No new road sources are introduced with the scheme, with impacts reflecting the increased use of an existing road. 4 Will the effect extend over a No. The two new exceedances are at two isolated points
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large area? with relevant exposure within the entire study area. The spatial extent of the effect is therefore miniscule. Around 99% of assessed receptors do not show any exceedance, either with or without the scheme.
The scheme covers a linear corridor 24 kilometres in length, with an Affected Road Network (ARN) of 140 kilometres in length, including 5305 potential receptors within 200 metres of the ARN. Representative receptors cover around 15.5km of affected area. 5 Will there be any potential for Not relevant as the potential for impacts are limited to within trans-frontier impact? 200 m of the affected road network. 6 Will many people be affected? No. Only two residential properties are indicated to have exceedances as a consequence of the scheme (2.5% of those assessed), with only 1% showing a „large‟ worsening with the scheme. There would be no other exceedances within the study area.
To put this into context, the two exceedances of representative receptors are not associated with any additional receptors that could be expected to show similar results: they are in isolation. 7 Will many receptors of other Not relevant for annual average NO2 concentrations after types (fauna and flora, gap analysis, which are assessed in relation to human businesses, facilities) be health effects only. affected? 8 Will valuable or scarce features Not relevant for local air quality thresholds for annual or resources be affected? average NO2. 9 Is there a risk that Yes, in terms of the AQS local air quality objective: the environmental standards will be scheme would result in two new exceedances, with one breached? undergoing a „large‟ worsening. 10 Is there a risk that protected Not relevant for annual average NO2 concentrations after sites, areas, or features will be gap analysis, which are assessed in relation to human affected? health effects only. 11 Is there a high probability of the The assessment including air quality modelling has been effect occurring? undertaken using relevant guidance including that provided by the HA, and the results for the 77 representative receptors have been verified against monitoring data (and adjusted where relevant). So overall, the probability is that the effect would be likely to occur. 12 Will the effect continue for a No. The effect should cease one year after the opening long time? year 13 Will the effect be permanent The effect is not permanent in the sense that it (the rather than temporary? concentration) is reversible over time, as shown in test question 6. 14 Will the impact be continuous Not relevant for local air quality as the threshold is an rather than intermittent? annual average. 15 If it is intermittent will it be Not relevant as it is not intermittent. frequent rather than rare? 16 Will the impact be irreversible? No, as demonstrated by test question 6 and item 12 above, the impact is reversible over time, well within the design life of the scheme. 17 Will it be difficult to avoid, or Significance reported here is without use of mitigation of reduce or repair or compensate gap analysis findings, and means of mitigating such change for the effect? are available for both new exceedances.
5.7.25 Using the Highway Agency draft evaluating significance approach and in the context of the EU criteria for evaluating significance, the overall conclusion on the M25 Section 5 scheme for local
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air quality (annual average NO2) is that there would be no overall significant effects on local air quality under LAQM.TG(09) based results.
Designated Sites - effects on vegetation and ecosystems Critical Levels
5.7.26 Annual mean NOx concentrations were estimated for transect receptors at the three Designated Sites that are sensitive to air pollution (Epping Forest SSSI and SAC (comprising 5 transects), Curtismill Green SSSI (1 transect) and Water End Swallow Holes SSSI (1 transect), for the base
year and 2015 DM and DS to indicate whether or not the annual mean Critical Level of NOx for the protection of vegetation of 30 µg/m3 would be exceeded and the effect of the scheme on concentrations. Estimated concentrations for transect receptors (shown in Figure 5.3) at the designated sites can be viewed in Volume 3, Appendix 5, Table A5.14. The following statements are based on the results presented in these tables. 5.7.27 Estimated concentrations at all seven transects exceed the 30 µg/m3 Critical Level at all receptors in the 2008 base year.
5.7.28 At Water End Swallow Holes NOx concentrations in 2015 are predicted to have declined from those in 2008 across the site and exceedances of the Critical Level are not expected. The scheme 3 would add a maximum of 0.1 µg/m of NOx to the total annual mean concentration at the nearest transect receptor which is expected as the NOx concentration is attributed to road traffic emissions from the A1(M) where traffic increases are small compared with the changes expected between Junction 23 and 27 on the M25. 5.7.29 At Epping Forest transects 1, 2 and 3, all transect receptors exceed the 30 µg/m3 Critical Level in both the DM and DS 2015 scenarios. The results presented in Appendix 5 Table A5.14 indicate that the scheme will result in estimated increases of more than 2 µg/m3, within approximately 150m of the road centreline. 5.7.30 Estimated concentrations at Epping Forest transect 4 to the east of the designated site exceed the 30 µg/m3 Critical Level within 185 m of the M25. The scheme would increase concentrations over 3 the DM, but would only add a maximum of 1.4 µg/m of NOx to the total annual mean NOx concentration at the nearest transect receptor to the road centreline. 5.7.31 The results for each transect show that concentrations in the DS scenario show the greatest increase as a result of the scheme at the transect receptors closest to the road. For most transects the increase in concentrations due to the scheme reduces with increasing distance from the road centreline. However for transect 3 and transect 4 there are some smaller increases at transect receptors closer to the road centreline that at those further away (115m on transect 3 and at 81m on transect 4). This is associated with terrain affecting plume dispersion in the GRAL model which is more evident at greater distances from the tunnel portals. 5.7.32 Comparison of the results for the different transects for Epping Forest south of the M25 indicates
that modelled concentrations of NOx are generally higher for transects near the eastern portal of the Bell Common Tunnel whilst sites near the western portal are much lower. 5.7.33 Estimated concentrations at the Epping Forest transect adjacent to the M11 exceed the 30 µg/m3 Critical Level at receptors within 90 m of the M11 in the DM and DS 2015 scenarios. The scheme 3 would add a maximum of 0.2 µg/m of NOx to the total annual mean concentration at the nearest transect receptor, due to the increase in road traffic emissions from additional traffic on the M11 as a result of the scheme. The increase in the volume of traffic on the M11 as a result of the scheme is of smaller magnitude that changes expected between Junction 23 and 27 on the M25.
As such the increases in concentrations of NOx are of smaller magnitude than those adjacent to the M25.
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5.7.34 Estimated concentrations at Curtismill Green SSSI transect, located between Junction 27 and 28 south of the M25, exceed the 30 µg/m3 Critical Level at all receptors in the DM and DS 2015 3 scenarios. The scheme would add a maximum of 0.5 µg/m of NOx to the total annual mean concentration at the transect receptor nearest the road.
5.7.35 For the purpose of assessing compliance with the EU Critical Level of NOx for the protection of vegetation “Sampling points targeted at the protection of ecosystems or vegetation must be sited more than 20 km away from agglomerations or more than 5 km away from other built-up areas, industrial installations or motorways or major roads with traffic counts of more than 50,000 vehicles per day” (ref. 5.3) The reason for undertaking air quality calculations is for the preparation of an Assessment of the Impacts on European Sites (AIES) under the Habitats Directive. The ecologist should consider the potential cumulative effects of the various impacts such as air pollution, water pollution and habitat loss and comment upon the effect of the project on the integrity of the Designated Site. Critical Levels - Significance
5.7.36 The HA spreadsheet tool to assist in evaluating significance is for NO2 at present: a number of the tests are not relevant to NOx, and a number would need recasting in their detail for use for NOx. On that basis, the evaluation of significance for designated ecological sites uses the main findings with the relevant questions from the EU guidance on judging significance, as shown in the table below. The full interpretation of significance of local air quality effects in terms of the Critical Level and Critical Loads at Designated Sites has been provided separately in Chapter 8 „Nature Conservation‟. 5.7.37 It is important to note that modelling results used in the significance evaluation do not include any mitigation applied to findings themselves. This should not be taken as implying that mitigation measures are not available to address any worsening arising from the scheme. 5.7.38 Reviewing the EU guidance on judging significance gives 11 of the 17 standard questions as being relevant for evaluating the significance of impacts at designated ecological sites. Responses to these 11 questions are shown in the Table 5.14 below. Table 5.14: EU Criteria for Evaluating Significance – M25 Section 5 Designated Ecological Sites (annual average NOx) Ref. EU Criteria Determination 1 Will there be a large change in No – the main change is in the future year Do Minimum environmental conditions? which is not associated with the scheme.
Whilst the scheme extends the area meeting the DMRB criteria of both an exceedance and at least a 2ug/m3 increase, this is only at 3 of the 7 transects, all in Epping Forest SSSI/SAC. Locations which meet this criteria exceed the critical level either with or without the scheme. 2 Will new features be out-of- Not relevant for local air quality – there are no new road scale with the existing sources introduced with the scheme, with impacts reflecting environment? the increased use of an existing road. 3 Will the effect be unusual in the Not for annual average NOx concentrations, as all receptors area or particularly complex? assessed show an increase in concentrations with the scheme, and receptors exceeding the threshold do so in the Do Minimum as well as the Do Something - apart from Epping Forest transect 4 where the with scheme extends the exceedance a further 30 metres (although the change is small).
No new road sources are introduced with the scheme, with impacts reflecting the increased use of an existing road. 4 Will the effect extend over a No – the effect can only be determined within a 200m large area? transect from the scheme corridor. For those transects
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exceeding, the extent of exceedance is unchanged (apart from a further 30m at Epping Forest transect 4, although the change here does not meet the DMRB criteria). 5 Will there be any potential for Not relevant as the potential for impacts are limited to within trans-frontier impact? 200 m of the affected road network. 6 Will many people be affected? Not relevant for annual average NOx concentrations. 7 Will many receptors of other There are 3 possible designated ecological sites of types (fauna and flora, relevance, and the effect can only be determined within a businesses, facilities) be 200m transect from the scheme corridor. Whilst the affected? scheme extends the area meeting the DMRB criteria of both an exceedance and at least a 2ug/m3 increase, this is only at 3 of the 7 transects, all in Epping Forest SSSI/SAC. Locations which meet this criteria exceed the critical level either with or without the scheme. 8 Will valuable or scarce features No, on the grounds that the features (designated ecological or resources be affected? sites) are regularly and easily included in the air quality assessment, and as such peculiar conditions do not have to be accounted for outside of the findings presented. 9 Is there a risk that No, the scheme does not cause breaches of the relevant environmental standards will be DMRB criteria of both an exceedance and at least a 2ug/m3 breached? increase, using available results. All locations meeting these criteria already exceed in the Do Minimum. 10 Is there a risk that protected Yes to an extent. For one (of the 3) designated ecological sites, areas, or features will be sites within 200m of the scheme corridor (Epping Forest), affected? there are existing (future year Do Minimum) concentrations which exceed the critical level and which worsen with the scheme by at least 2ug/m3.
This affect does not cover the whole of the Epping Forest SSSI/SAC as transect 4 towards the eastern portal of the M25 and the separate section around the M11 both have increases less than a 2ug/m3 change. 11 Is there a high probability of the The assessment including air quality modelling has been effect occurring? undertaken using relevant guidance including that provided by the HA, and the results have been verified against monitoring data (and adjusted where relevant). So overall, the probability is that the effect would be likely to occur. 12 Will the effect continue for a The increment to NOx from the scheme is unlikely to long time? remain significant by the design year. For illustration the road increment to total Nitrogen deposition is no more than 1%. 13 Will the effect be permanent The increment to NOx from the scheme is unlikely to rather than temporary? remain significant by the design year, and so the effect would not be classified as permanent. 14 Will the impact be continuous Not relevant for local air quality as the threshold is an rather than intermittent? annual average. 15 If it is intermittent will it be Not relevant as it is not intermittent. frequent rather than rare? 16 Will the impact be irreversible? Not relevant given the premise that air quality vehicle related impacts are reversible. 17 Will it be difficult to avoid, or Significance reported here is without use of mitigation of reduce or repair or compensate findings, and means of mitigating such change are available for the effect? in many cases.
5.7.39 Using the Highway Agency draft evaluating significance approach and in the context of the EU criteria for evaluating significance, the overall conclusion on the M25 Section 5 scheme for the
effect of annual average NOx on designated ecological sites is that there would be no overall significant effects. The overall view on significance for designated ecological sites (balancing various environmental topics) is contained within Chapter 8 „Nature Conservation‟.
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Critical Loads 5.7.40 Estimated N deposition rates for the Designated Sites are given in Volume 3 Appendix 5, Table A5.15. 5.7.41 The results of the assessment of change in N deposition rates determines whether the critical load, established for the air pollutant sensitive features of the designated site, is exceeded and whether the scheme will result in an increase in N deposition rates. 5.7.42 For the Water End Swallow Holes transect, deposition rates are above the Critical Load of 10 - 20 kgN/ha/yr at all transect receptors, in the DM and the DS in 2015. The road only contributes up to 1.2% as an increment of the total N deposition rate, and there is a negligible change in the road increment as a result of the scheme. 5.7.43 For the Epping Forest transects 1, 2 and 3 receptors, deposition rates at all transect receptors are above the Critical Load of 10-20 kgN/ha/yr in the DM and the DS in 2015. This is attributed to the high background deposition rate of 29.4 kgN/ha/yr, as shown in Table 5.7, which exceeds the Critical Load before the road increment is added. The M25 contributes up to 17% to the total deposition rate at the transect receptor nearest to the road and the scheme increases the road increment by up to 0.4 kgN/ha/yr 5.7.44 For the Epping Forest transect 4, located near to the western Bell Common Tunnel portal, deposition rates are above the Critical Load of 10 - 20 kgN/ha/yr at all transect receptors, in the DM and the DS in 2015. As for transects 1, 2 and 3, this is attributed to the high background deposition rate affecting Epping Forest south of the M25. Whilst the modelled roads contribute up to 3% at the transect receptor closest to the road, as an increment of the total N deposition rate, the scheme increases the road increment contribution by up to 0.1 kgN/ha/yr . 5.7.45 For the Epping Forest transect adjacent to the M11, deposition rates are above the Critical Load of 10 - 20 kgN/ha/yr at all transect receptors, in the DM and the DS in 2015. The high deposition rates are attributed to the background deposition rate of 30.3 kgN/ha/yr, as shown in Table 5.7, whichexceeds the upper bound of the Critical Load before addition of the road increment. Whilst the road contributes up to 5% as an increment, there is a negligible change in the road increment (change of less than 0.1 kgN/ha/yr as a result of the scheme. 5.7.46 For the Curtismill Green SSSI transect, deposition rates are below the lower bound of the critical load of 20 - 30 kgN/ha/yr, in the DM and the DS in 2015. The background deposition rate at this site is 15.5 kgN/ha/yr and the road increment at the transect receptor closest to the road, is 6% of the overall deposition rate. The maximum increase in deposition rate as a result of the scheme is 0.1 kgN/ha/yr. The results appear to indicate that the change in deposition increases at 197 m from the road, however this is a result of the small changes in NOx concentrations being rounded within the deposition calculation to indicate a larger change and not an effect of road emissions increasing at the greatest distance from the road. Epping Forest SAC and SSSI south of the M25 and Epping Forest SSSI adjacent to the M11 and Water End Swallow Holes SSSI were all found to have background N deposition rates which exceed the critical loads specified for the most sensitive features found on site. The scheme increases the road increment contribution to total N deposition by a maximum of one percent. There are no guidelines for assessing the significance of changes in N deposition rates, however the results of this assessment are considered within the ecological impact assessment, where the cumulative effects of impacts such as air pollution, water pollution and habitat loss are considered. Regional Air Quality Effects 5.7.47 Total emissions from roads included in the regional air quality ARN (54 qualifying road sections
only) have been estimated for carbon as CO2 equivalent, NOx, PM10 and hydrocarbons in 2008 (base year) and with and without the scheme in 2015 (opening year) and 2030 (design year). The results are shown in Appendix 5, Volume 3, Table A5.16. A summary table presenting the regional results is provided in Table 5.15.
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5.7.48 The Regional ARN shown in Volume 3, Appendix 5, Box A5.1 includes the mainline sections of the M25 between junctions 23 and 27, a number of associated slip roads, and a small number of smaller roads where the change in flow is greater than 10% but still relatively small, (not exceeding LAQ criteria of changes of 1000 AADT or more, indicating potential to affect local air quality). 5.7.49 In 2015, the regional assessment indicates that emissions of all local air pollutants will be increased as a result of the scheme on the 54 links included. The emission increases are between 10 and 12% for all pollutants. In 2030 the emissions estimates indicate an increase of between 14 to 18% as a result of the scheme. These increases are due to the additional traffic, which would attracted by the scheme.
5.7.50 Overall, reductions in emissions of NOx, PM10 and hydrocarbons of between 46 and 80% are estimated by 2030 when compared with 2008 levels as expected improvements in vehicle technologies becoming more prevalent within the vehicle fleet over time as older, more polluting technologies are replaced. For carbon dioxide future fleet improvements do not mitigate the predicted increase in vehicle kilometres travelled, which is expected to increase by 30% in 2015 and 53% in 2030 when compared to the base year. By 2015 an increase in carbon dioxide emissions of 20% is expected when compared with the base year emissions. In 2030 the increase in carbon dioxide emissions compared to base year levels is 30%. 5.7.51 Overall, the regional emissions are based on only 54 road sections from the traffic model, however they do include the scheme and the mainline motorway sections with changes in flow of greater than 10% and provide a reasonable estimate of the largest changes in emissions as a result of the scheme. Table 5.15: Regional Emissions
Total Total Total Total Emissions Total Annual Scenario emissions CO emissions NO Emissions PM Hydrocarbons kg/yr 2 x 10 Vehicle km T/yr (% change) kg/yr (% change) kg/yr (% change) (% change)
Base Year (2008) 311711 1724633 56614 134874 1,160,478,222
DM (2015) 334096 845262 32403 43787 1,339,696,161
DS (2015) 372834 932997 36324 48523 1,504,636,116
Change from DM 38738 (12%) 87735 (10%) 3921 (12%) 4736 (11%) 164,939,956 (12%) (2015)
Change from Base 61123 (20%) -791636 (-46%) -20290 (-36%) -86351 (-64%) 344,157,894 (30%) Year (2008)
DM (2030) 349008 293450 21493 64095 1,536,680,970
DS (2030) 406322 347144 24709 72923 1,779,330,890
Change from DM 57314 (16%) 53694 (18%) 3216 (15%) 8828 (14%) 242,649,920 (16%) (2030)
Change from Base 94611 (30%) -1377489 (-80%) -31905 (-56%) -61951 (-46%) 618,852,667 (53%) Year (2008)
Construction Dust Impacts 5.7.52 There are 1,971 potentially sensitive properties within 200 metres of the boundary of construction works (shown in Figure 5.4). Potentially sensitive ecologically Designated Sites within 200 m of the boundary of construction works include Epping Forest SAC/SSSI and Curtismill Green SSSI.
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5.7.53 Given the nature of the works and on the basis that appropriate mitigation to control dust during construction is applied, which would control emissions to within the working site boundary, it can be concluded that the effects would be negligible. WebTAG Local Air Quality Impacts 5.7.54 In line with the requirements of DMRB HA207/07 (paragraph 3.4), a summary of the findings of the local air quality appraisal prepared for the Appraisal Summary Table using the Transport Appraisal Guidance (TAG) (ref 5.26) is included in the EAR as an indication of the overall change in air quality. 5.7.55 The local air quality assessment has been undertaken following the procedure given in TAG Unit 3.3.3 The Local Air Quality Sub-Objective, April 2012 (ref 5 26). Further details are provided in the AST Report for Section 5 MM2 All Lanes Running and the results for other local air quality related elements of the TAG assessment, including: additional assessments associated with TAG Unit 3.15.5 The Treatment of Uncertainty in Model Forecasting, April 2011; and the assessment of social and distributional impacts of air quality in accordance with TAG Unit 3.17 Detailed Guidance on Social and Distributional Impacts of Transport Interventions, April 2011. 5.7.56 TAG local air quality calculations have been undertaken using the DMRB air quality screening tool and associated tools from Defra‟s Local Air Quality Management Technical Guidance, February 2009 for the DM (i.e. without the scheme) and DS (i.e. with the scheme) scenarios in the scheme opening year of 2015. 5.7.57 The local air quality assessment for TAG considers the local air quality affected road network only. The assessment has used the same definition of local air quality affected road network as used in the main EAR assessment of local air quality. As such the affected road network is that shown in Volume 2 Figure 5.1. 5.7.58 The TAG local air quality assessment gives a quantitative indication of whether the scheme would lead to an overall improvement or deterioration in air quality at properties. The local air quality summary worksheets are included in Volume 3, Appendix 5, Table A5.17 and Table A5.18. The overall AST for the project is shown in Volume 3, Appendix 4 (all topics).
5.7.59 The assessment shows that in terms of annual mean NO2 there is an overall improvement, as indicated by the negative net total assessment score of -21, however the net total assessment score is very low indicating the difference between the DM and the DS is small. Indeed, the overall change in the net total assessment score between the DM and DS is less than 0.1% of the DM net
total assessment score both for NO2. 5.7.60 For the core traffic growth scenario a similar number of properties experience an improvement in
annual mean NO2 concentrations as experience a deterioration: 44% of the properties (2321 in total) experience an improvement (i.e. a decrease in NO2 concentrations) and 44% (2345 in total)
experience a deterioration (increase in NO2 concentrations) whilst 12% (639 in total) show no change in concentrations with the scheme.
5.7.61 In terms of annual mean PM10 the net total assessment score is similar to NO2 results, with an overall improvement although the net total assessment score is even lower than for NO2 at -5. NO2 and PM10 have differing speed-emission relationships which can result in a different overall result for NO2 and PM10. 5.7.62 In terms of determining whether there are exceedances with the scheme at receptors the results for the EAR should be used. The concentrations calculated for the TAG local air quality assessment are unverified as modelling is not undertaken at specific receptors and the methodology specified in TAG is simplistic. Air quality modelling for the EAR was undertaken
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using a dispersion modelling approach that is able to better reflect local conditions and includes verification against local monitoring including model adjustment where appropriate. 5.8 Supplementary Information 5.8.1 Since undertaking the air quality assessment, in accordance with the DMRB methodology, and
reported in this EAR, Defra issued (30 April 2012) a note on the projection of long term NO2 concentrations (ref. 5.77). Definitive guidance is being developed to consider this for application to all Highway Agency affected schemes. As a result, in the project timescales, an interim assessment has been undertaken based on developing Draft Guidance to help the consenting authority to understand the likely impacts on any significant effects from long term trends, and is reported on in Volume 3, Air Quality Annex 7. 5.9 Indication of Any Difficulties Encountered 5.9.1 No comments are required. 5.10 Summary 5.10.1 An air quality assessment of the scheme has been undertaken in accordance with the DMRB HA207/07. The assessment includes consideration of: Local air quality effects at representative receptors, in terms of human health and Designated Sites with ecologically sensitive features, as a consequence of the scheme in 2015 (the first full year after scheme opening) Regional air quality effects, in terms of changes in emissions as a consequence of the scheme in 2015 and 2030 (the design year) Construction dust impacts, in terms of relevant sensitive receptors within 200 m of the scheme 5.10.2 An assessment in accordance with WebTAG was also undertaken. This is reported separately, but the key findings have been summarised within this EAR. 5.10.3 Using the Highway Agency draft evaluating significance approach and in the context of the EU criteria for evaluating significance, the overall conclusion on the M25 Section 5 scheme for local
air quality (annual average NO2) is that there would be no overall significant effects on local air quality under LAQM.TG(09) based results for human health impacts. 5.10.4 Using the Highway Agency draft evaluating significance approach and in the context of the EU criteria for evaluating significance, the overall conclusion on the M25 Section 5 scheme for the
effect of annual average NOx on designated ecological sites is that there would be no overall significant effects. The results of the air quality assessment for Designated Sites have been passed on to the project ecologist for inclusion in the ecological impact assessment. 5.10.5 Assessment of the changes in total N deposition as a result of the scheme indicate that deposition rates are higher than the Critical Loads for the sensitive features at Epping Forest and Water End Swallow Holes, mostly attributed to the high background N deposition rates. Deposition rates were below the Critical Load at Curtismill Green. The maximum increase in the road increment contribution to the total N deposition rates is 0.4 kgN/ha/yr compared to the Do Minimum, which is a change of 1%. The results of the total N deposition for Designated Sites have been passed on to the project ecologist for inclusion in the ecological impact assessment. 5.10.6 The regional assessment indicates that there would be increases in emissions with the scheme of between 10 and 12% in 2015 and between 14 and 18% in 2030, compared with the DM scenario. There is a reduction in all emissions in 2015 and 2030, with the exception of carbon presented as carbon dioxide equivalent, when compared with the base scenario.
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5.10.7 In terms of construction, with mitigation measures in place (these would be implemented on the construction site and not at individual receptors), the risk during construction would be low risk. Construction would therefore be unlikely to cause a statutory nuisance. 5.10.8 The assessment concludes that there would be no significant effects on air quality.
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6. Cultural Heritage 6.1 Study Area 6.1.1 The Study Area for Cultural Heritage extends to 500 metres either side of the centreline of the M25 from Junctions 23 to 27 and is shown on Figure 6.1. The baseline information obtained within this assessment included all designated heritage assets within the 500 metre Study Area. 6.2 Baseline Conditions 6.2.1 The data used to support this initial analysis has been derived from a number of sources including: M25 Junction 23 to 27 – Section 5, Managed Motorways – Options Assessment Environmental Assessment Report (April 2010). National Monuments Record (NMR) GIS data sets for details of Listed Buildings, Registered Parks and Gardens, Scheduled Monuments. The National Heritage List for England online database maintained by English Heritage (last accessed 13th July 2011). Local authority websites for details of planning policy related to the historic environment and to check Conservation Area designations. Local authorities within the study area include: Hertsmere Borough Council, Welwyn Hatfield Borough Council, London Borough of Enfield, Broxbourne Borough Council, Epping Forest District Council. 6.2.2 Data was gathered for the following types of designated heritage assets: Listed Buildings Registered Parks and Gardens Scheduled Monuments Conservation Areas 6.2.3 No World Heritage Sites, Protected Wreck Sites or Registered Battlefields are present within the study area. 6.2.4 The data collected is considered sufficient to prepare an assessment of the likely impact of the proposed scheme on the setting of designated heritage assets. Further details on the scope of the assessment are set out in the Methodology - Section 6.3 of this report. 6.2.5 An initial site visit was undertaken in July 2011 with a further site visit in February 2012 to assess the views and settings of heritages sites and how the Project may change these. 6.2.6 A full list of sites is contained within a Gazetteer in Appendix E and are shown on Figures 6.1. 6.3 Methodology Scope of Assessment 6.3.1 Guidance contained in Section 5 of the Interim Advice Note 111/09 for Managed Motorways Implementation guidance - Hard shoulder running (Highways Agency, November 2009) outlines that as most projects are contained within „disturbed‟ highway boundary, impacts on buried archaeology are considered to be unlikely. Any potential impacts are therefore likely to be limited to receptors off site such as the effects on the setting of heritage assets. 6.3.2 As identified in the Project Description in Section 2 of this report, the Project would be contained within the existing highway boundary. Consequently, it does not consider below-ground archaeological issues. Additionally, as the Project is contained within the highway boundary and
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does not include substantial new development it would not significantly alter the character of the wider historic landscape. This report therefore does not consider historic landscape character issues. 6.3.3 The Project requires the erection and operation of gantries and cantilever message signs of varying forms along the route corridor. It would also require the installation of Emergency Refuge Areas (ERAs) and the use of the hard shoulder for running traffic . The installation and operation of these elements has the potential to affect the visual and aural setting of heritage assets along the route corridor. 6.3.4 Construction details such as compound sites, storage areas etc are not known at this stage and are therefore not considered within the report. 6.3.5 This assessment is therefore concerned with the potential visual and aural impacts as a result of construction and operation of the Project on the setting of designated heritage assets. Assessment Methodology 6.3.6 The assessment has been undertaken in accordance with the three stage approach as set out in DMRB. First, the value of the heritage asset is assessed, then the magnitude of impact (taking into account agreed mitigation measures) is identified, and finally the significance of effect is determined by using a matrix and professional judgement to combine the magnitude of the impact and the value of each asset. The criteria for assessing the value of assets; the magnitude of the impacts and the significance of effect can be found in DMRB Volume 11, Section 3, Part 2 Cultural Heritage. 6.3.7 The impacts to the designated heritage assets from this Project are liable to be both short and long-term, both with the temporary impacts of the construction phases, and the long-term change through the completion of the Project. 6.4 Value (Sensitivity of Resource) 6.4.1 The relative values of the designated heritage assets have been set out in Table 6.1 below as part of the impact assessment. 6.5 Regulatory/Policy Framework National Policy Planning (Listed Buildings and Conservation Areas) Act 1990 6.5.1 The Act relates to special controls in relation to buildings of special historic or architectural interest and restricts any works for the demolition of a listed building or for its alteration or extension in any manner which would affect its character as a building of special architectural or historic interest unless the works are authorised for example by being given Listed Building Consent The Act also controls works involving demolition of buildings within Conservation Areas. National Planning Policy Framework 6.5.2 Policy 12 of the NPPF sets out national guidance on conserving and enhancing the historic environment and replaces PPS5. It is considered that Policy 12 maintains the level of protection that PPS5 gave to heritage assets. 6.5.3 NPPF Policy 12 reflects the principles of PPS5, in that it deems historic environment assets, as natural environment assets, to be an irreplaceable resource to hand on to future generations. The NPPF emphasises the desirability of sustaining and enhancing the significance of heritage assets and putting them to viable uses (consistent with their conservation) focussing on the wider social, cultural, economic and environmental benefits that conservation of the historic environment can bring. Paragraphs 128 – 136 describe development management procedures. As under PPS 5,
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where development affects the historic environment justification is required to be made by the developer of any effects on historic environment assets in relation to their significance. Regional Policy The London Plan 2011 6.5.4 The London Plan, 2011 includes the following relevant policy: Policy 7.8 – Heritage Assets and Archaeology Strategic A) London‟s historic environment, including natural landscapes, conservation areas, heritage assets, World Heritage Sites, Scheduled Ancient Monuments and memorials should be identified, preserved and restored. B) Development should incorporate measures that identify, record, interpret, protect and, where appropriate, present, the site‟s archaeology. Planning decisions C) Development should preserve, refurbish and incorporate heritage assets, where appropriate. D) New development in the setting of heritage assets, and conservation areas should be sympathetic to their form, scale, materials and architectural detail. E) New development should make provision for the protection of archaeological resources and significant memorials. Where the artefact or memorial cannot be moved from the site without damaging its cultural value, the assets should where possible be made available to the public on- site. Local Policy 6.5.5 The development plans of the five District/Borough councils, along with the London Plan, set out the policies of local authorities towards heritage assets in relation to the planning process. The policies adhere to the principles of national planning guidance discussed above, in that the importance of these resources is recognised and that provision is made for their protection within the planning process. Hertsmere Borough Council Hertsmere Local Plan – 2003 6.5.6 Hertsmere Borough Council Local Plan includes the following policies: E9: Assessment of sites “Where a proposal for development may affect remains of archaeological significance, or may be sited in an area of archaeological potential, developers will be required to undertake an archaeological field assessment and submit a report on the findings to the local planning authority before a planning application is determined.” E10: Nationally important sites “Planning permission will not be granted for development that will adversely affect Scheduled Ancient Monuments, or other nationally important archaeological sites and monuments, or their settings.” E11: Sites of less than national importance “Planning permission will only be granted for development which affects archaeological remains of less than national importance or their settings, if the merit of the development outweighs the importance of the remains. If planning permission is given for development which would affect remains, conditions will be imposed to ensure that the remains are properly recorded, and where practicable, preserved and enhanced, and the results analysed and published.”
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E16: Development affecting the setting of a Listed Building “Planning permission will be refused for any development which would materially harm the setting of, or endanger the fabric of, a listed building.” Hertsmere Revised Core Strategy Development Plan Document, Consultation Draft - 2010 6.5.7 The following policy is relevant: Policy CS13 Protection or enhancement of historic assets “All development proposals must preserve or enhance the historic environment of the Borough in order to maintain and where possible improve local environmental quality. Development proposals should be sensitively designed to a high quality and not cause harm to identified, protected sites or locations of historic or archaeological value including Conservation Areas, Listed Buildings, Historic Parks and Gardens, Scheduled Ancient Monuments and Archaeological Remains.”
Borough of Broxbourne Broxbourne Local Plan – 2005 6.5.8 Borough of Broxbourne Local Plan includes the following policies: HD1: Effect of development on nationally important sites and monuments “Planning Permission will not be granted for development which would adversely affect the site or setting of nationally important archaeological remains, whether scheduled or unscheduled.” HD2: Requirements for evaluation of heritage asset “The application for development on, or adjacent to, sites of known archaeological interest or sites believed to possess potential archaeological significance, will be required to submit the results of an archaeological field evaluation prior to determination of any application for development.” HD3: Preservation of heritage asset (i) “Where the council considers that archaeological sites or monuments of Local Importance and their settings are likely to be affected by development, physical preservation in situ will be the preferred option. The decision whether to preserve in situ will be made on the basis of the intrinsic importance of the remains and the possibility of preservation in situ through the careful design, layout and sitting of new development. Where preservation in situ is not merited, planning permission may be subject to conditions and/or legal agreement requiring that provisions be made for the investigation and recording of the remains and publications of a report of findings prior to commencement of the development. (ii) The council will: (A) Seek to secure the appropriate management and presentation of archaeological sites and their settings as part of the grant of planning permission for development; (B) Ensure designs for development in the vicinity of archaeological remains are sympathetic to the setting of the remains; and require the developer to allow observation of groundwork‟s. (where the council considers that physical preservation of archaeological remains in situ is not merited, taking into account the importance of the remains and other material considerations, planning permission may be subject to conditions and/or agreements requiring the developer to secure appropriate provisions for the investigation and recording of the archaeological remains and the publication of the results. Where appropriate, the council will seek to secure the enhanced management and presentation of archaeological sites and their settings.)
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(iii) Additionally the council will: (A) Seek to secure the enhancement, management and presentation of archaeological sites and their settings as part of the grant of a planning permission for development; (B) Ensure designs for development in the vicinity of archaeological remains are sympathetic to the setting of remains; and (C) Require the developer to allow observation of groundworks.”
HD6: Other development affecting Listed Buildings and its curtilage “Development within the cartilage of a Listed Building, and development which affects the setting of a Listed Building will only be permitted where the proposed is appropriate in terms of preserving the character and/or setting of the building and will not be prejudicial to other policies of this plan.” HD9: Parks and Gardens of Historic Interest “Planning Permission will not normally be granted for development which would have an adverse effect on the character and setting of a historic Park or Garden. The council will encourage retention and, where appropriate, restoration of any historic Park or Garden within the Borough.” Broxbourne Submission Core Strategy - 2010 6.5.9 The Broxbourne Submission Core Strategy includes the following policy is relevant: Policy CS8 – Environment (summarised) “To help conserve and enhance the natural, historic and built environment: All sites in and adjoining the borough which are protected by the planning system or of important landscape, wildlife, scientific and/or archaeological value will be conserved and enhanced in accordance with national guidance and local objectives. All buildings and areas which are protected by the planning system or with local built environment merit will be conserved and enhanced in accordance with national guidance and local objectives.” Welwyn Hatfield District Plan – Welwyn Hatfield Borough Council, 2005 6.5.10 Welwyn Hatfield District Plan includes the following relevant policies: R28: Historic Parks and Gardens “Development will not be permitted if it would lead to the loss of, or cause harm to, the historic character, appearance or setting of any part of a registered historic park or garden. Proposals for development in any unregistered historic parks and gardens listed in Appendix 3 will be considered in terms of their contribution to the quality and character of the historic environment. The Council will work with the County Council, the Hertfordshire Building Preservation Trust and the Hertfordshire Gardens Trust to promote the preservation and maintenance of this resource.” London Borough of Enfield Enfield Unitary Development Plan – 1994 6.5.11 The London Borough of Enfield Unitary Development Plan includes the following relevant policies: C1: Archaeology and Ancient Monuments “To ensure that, where appropriate, areas, sites, buildings and landscape features of archaeological, architectural or historical interest, together with their character and setting, are preserved or enhanced.”
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C4: Archaeology and Ancient Monuments “To encourage suitable design, land use and management so as to safeguard archaeological sites, and to seek to ensure that the most important archaeological remains and their settings are permanently preserved (if necessary for public access and display) and that, where appropriate, they are given statutory protection.” C19: Historic landscape “To ensure in the case of historic landscapes that: (a) Development within such landscapes does not diminish their character and interest; (b) Opportunity is taken to secure comprehensive schemes for the repair, maintenance and future management of these landscapes in association with any development proposals therein.” Epping Forest Local Plan – Epping Forest District Council, 2008 6.5.12 The Epping Forest Local Plan includes the following relevant polices: HC3: Historic landscape “The council will not grant planning permission for development which could adversely affect the areas of registered Parkland (identified as such on the proposal maps).” HC12: Listed Buildings “The council will not grant planning permission for development which could adversely affect the setting of a Listed Building.” The Enfield Plan, Core Strategy – 2010 6.5.13 The Enfield Plan includes the following relevant policy: Core Policy 31: Built and Landscape Heritage The Council will implement national and regional policies and work with partners (including land owners, agencies, public organisations and the community) to pro-actively preserve and enhance all of the Borough's heritage assets. Actions will include:
Reviewing heritage designations and their boundaries where appropriate, and continuing to maintain non-statutory, local lists and designations based on formally adopted criteria; Ensuring that built development and interventions in the public realm that impact on heritage assets have regard to their special character and are based on an understanding of their context. Proposals within or affecting the setting of heritage assets will be required to include a thorough site analysis and character appraisal which explicitly demonstrates how the proposal will respect and enhance the asset; Identifying opportunities for the repair and restoration of heritage assets and working with owners of heritage assets on English Heritage‟s Heritage at Risk Register to find viable solutions to secure the asset‟s long-term future. Where necessary, the Council will make full use of its legislative powers to ensure their preservation; Ensuring developments in areas of archaeological importance take into account the potential for new finds by requiring consultation with English Heritage and on-site investigations, including the appropriate recording and dissemination of archaeological evidence; Supporting appropriate initiatives which increase access to historic assets, provide learning opportunities and maximise their potential as heritage attractions, particularly at Forty Hall and the Area of Special Character in the north west of the Borough; and Finding new ways to record and recognise Enfield‟s intangible heritage resources and, where possible, open up wider public access to them.
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6.6 Design, Mitigation and Enhancement Measures 6.6.1 A process of early strategic appraisal has been carried out in conjunction with the design engineers and other specialists. The design proposals have been through a process of review and alteration prior to finalising the design. One of the elements considered along with other disciplines was the distance of designated heritage assets from the Project. 6.6.2 As part of this review, the number of gantries required as part of the Project was reduced. Where the settings of designated heritage assets could be affected, adjustments were made to the design where feasible (for example the movement of a gantry position) .By reviewing the design and proposing mitigation in the form of screening, the design has been optimised to ensure as minimal an affect as possible on designated heritage assets. 6.7 Magnitude of Impacts (Change) and Significant Effects Construction 6.7.1 All the known heritage assets lie outside of the highways boundary with the exception of Copped Hall Registered Park and Garden. The works within Copped Hall Registered Park are to take place within the highways boundary adjacent to the carriageway and as so they will not affect the planted / green space or any physical aspect of the park itself. 6.7.2 There may however be impacts as a result of the proposals on the settings of designated heritage assets through increased noise or vibration as well as visual changes. Through the construction period, these will be temporary effects. The methods of construction and routes for construction traffic have not yet been set out and so are outside of the scope of this assessment.
Operation 6.7.3 The long-term post-construction impacts relate to changes to the setting of designated heritage assets. As set out above this can be as a result of visually intrusive signage, increased traffic flows, increased noise or vibration which if appreciable and noticeable may change the character and ambience of the asset‟s setting. 6.7.4 In terms of traffic increases, the scheme is proposed in order to improve flow along the M25 carriageway rather than just increasing capacity. Traffic is set to increase by approximately 10% as a result of the scheme being construction (as at Design Year 2015 based on a comparison of Do Minimum and Do Something). The flows are set to change from approximately 160,000 vehicles per day (AADT flows at Do Minimum) to nearly 180,000 vehicles per day (AADT flows at Do Something). In terms of the wider road network, increases on the surrounding road network would not be significant. 6.7.5 Table 6.1 set out below has assessed designated heritage assets within the study area and in line with DMRB guidance has set out the value of the asset, the magnitude of impact and the resulting significance of the effect. The description of likely impact has taken into account the changes to visual changes as a result of the signage as well as potential affects as a result of increased noise, vibration and traffic flows based on the information set out above.
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BH Ref / NMR No. / Outline description of Value Description of likely impact including potential Magnitude of Impact Significance of Figure Ref Designated Asset mitigation measures Effect BH53 / 6.1 Sheet 1 Grade II Listed brick road Medium The bridge is surrounded by trees each side of the No change Neutral bridge over Mimmshall Brook Brook. The nearest gantry proposals are c. 300m to on the A1081. the north west and 480m to the north east where proposals are to modify an existing gantry (CH37770) and to remove an existing gantry (CH38230). There will be no change to the setting of the bridge. BH 49 – 51 / 6.1 Dancer‟s Hill House, Medium Both the house and farmhouse are set within large No change Neutral Sheet 1 Farmhouse and Grotto – all grounds and are enclosed by trees particularly to the Grade II Listed on Dancer‟s north and west, obscuring views of the motorway. Lane. A large villa with grotto The nearest proposals are the removal of a gantry in the grounds and farmhouse (CH38230) c. 270m to the north of the farmhouse further to the north along the and the introduction of a new gantry (GB38430) c. lane. 170m further to the east, (c. 400m to the east of the farmhouse). There will be no change in views from these buildings as a result of the existing tree screening. BH48 / 6.1 Sheet 1 Elm Farm House- Grade II Medium The house is designed to have views from the front No change Neutral Listed brick two storey house of the house to the south west, away from the with larger house to the east carriageway. Long reaching views along the and barns to the west. motorway carriageway from the back of the house to the north west are prevented by trees and by surrounding buildings on the plot. New cantilevers are proposed at GB39610 and at GA39720 to the north west of the house, but will be behind trees and in a cutting. Cantilevers at GB39460, GA39380 and GB39235 will be obscured from the farm house by an intervening property and by trees immediately surrounding the house and along Bentley Heath Lane.
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BH Ref / NMR No. / Outline description of Value Description of likely impact including potential Magnitude of Impact Significance of Figure Ref Designated Asset mitigation measures Effect BH 44 – 47 / 6.1 Group of buildings on Bentley Medium Trinity Chapel and the Almshouses are nearly 500m No change Neutral Sheet 1 Heath Lane including Trinity to the south of the carriageway, and do not have a Chapel, Bentley Heath view of the road. Farmhouse and Barn and a Bentley Heath Farmhouse and its Barn to the north set of Almshouses. All Grade west are c 170m to the south of the carriageway and II Listed. surrounded by large modern agricultural buildings. The carriageway is in a deep cutting at this point although there is a new gantry proposed directly to the north east of the farm (GAB40120).Due to the depth of the cutting, together with the screening provided by the large agricultural buildings to the north west of the farmhouse and barn, there will be no change to the setting of the buildings. Wrotham Park / 6.1 Wrotham Park – Grade II High The majority of Wrotham Park is more than 500m No change Neutral Sheet 1 Registered Park and Garden. from the M25 carriageway. Only the north eastern A country house surrounded edge of the park lies within the study area. To the by 18th century landscaped north of the park is a thick belt of trees lining park. The park was not Dancer‟s Hill Road which limits views to the north. accessed as it is privately The Registered Park and Garden designation owned, however views from description describes long reaching views to the the northern boundary of the west, which do not include the motorway. park along Dancers Hill Road were assessed. BH 52 / 6.1 Sheet 1 Grade II Listed Duke of York Medium The pub faces to the south east with the large No change Neutral public house, located on the extension to the rear preventing views to the north. junction of Dancers Hill Road Tree planting and a large garden centre to the north and the Barnet Road (known prevent views of the motorway. locally as Ganwick Corner). Building currently a restaurant with large modern extension to the rear.
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BH Ref / NMR No. / Outline description of Value Description of likely impact including potential Magnitude of Impact Significance of Figure Ref Designated Asset mitigation measures Effect The Royds, Potters Conservation Area comprising Medium Only the southern tip of the Conservation Area lies No change Neutral Bar Conservation a planned estate of avenues within the study area i.e. Oakroyd Close and Area / 6.1 Sheet 1 and closes with houses and Oakroyd Avenue. Although the topography prevents bungalows designed in a full views of the motorway from the rear of properties chalet style. Located on the in the Conservation Area and any road views are in very south eastern extent of any case dominated by a cluster of tall pylons, there Potters Bar c. 450m to the may however be glimpsed views of the new north of the M25. cantilever signs and gantries proposed to the south (GA39720, GB39610 and, GAB40120), above the cutting in this section. The occasional glimpses of the motorway with gantries will not however affect the setting of the Conservation Area. BH 34 / 6.1 Sheet 2 North Lodge is a large late Medium The principal (front) facade has views to the south Minor Slight Adverse 18th century house in a away from the carriageway. The rear façade, classical style with later however, has been designed to take advantage of additions. Now a school. views to the north, with a large projecting first floor Grade II Listed. bay window supported by timber columns. The view is currently dominated by the road, but is shielded in the immediate foreground by a thin group of trees. The surrounding buildings and trees in the grounds prevent long reaching views to the east and west along the carriageway, but there will be a clear view of GB43300 and GA43160. This will increase further the visual presence of the motorway from the house and grounds but will only alter one minor aspect of this asset‟s significance. Onsite screening would enhance the current views. BH 54 / 6.1 Sheet 2 Grade II Listed two storey Medium The farmhouse is set within a number of more No change Neutral colour washed farmhouse – modern agricultural buildings and barns. The Cattlegate Farm. Access to farmhouse is c. 300m from the carriageway which is this farmhouse was not on an embankment at this location. The farmhouse obtained as it is located along is orientated south west / north east. The cantilever a gated private access track. GA45760 is likely to be obscured from view by surrounding farm buildings and by screen planting on the embankments along the carriageway. BH 32, 55 & 56 / 6.1 Owls Hall Farmhouse is a Medium Owls Hall Farmhouse is located c. 125m south of the Negligible Neutral
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BH Ref / NMR No. / Outline description of Value Description of likely impact including potential Magnitude of Impact Significance of Figure Ref Designated Asset mitigation measures Effect Sheet 3 Grade II Listed two storey carriageway. The house is surrounded by a number stuccoed villa. Access was not of buildings as well as tree planting within the obtained as it is located along grounds. In addition there is a thick line of trees a private access track, but planted alongside the carriageway at this location views were assessed from providing some screening. A gantry is proposed nearby Cattlegate Road. directly to the north of this building, but on the opposite side of the carriageway (GAB45760) which is unlikely to be visible above the trees and surrounding buildings. BH 55 & 56 / 6.1 Paddocks Farmhouse (Grade High The farmhouse is on the southern side of a complex Negligible Neutral Sheet 3 II*) and barns to the north of buildings with barns to the north west and further west (Grade II Listed). outbuildings surrounding them. While there is a cantilever proposed directly to the north of the farm complex (GB46100), it is over 450m to the north and will not be a significant element in the views north from the farm. Nearby ERAs will be entirely screened from the property by woodland. Onsite screening of the new cantilever would help shield the house further from the road. BH 59 / 6.1 Sheet 3 Burnt Farm Cottage, Grade II Medium Farm cottage c. 500m to the north of the No change Neutral Listed farm cottage. carriageway behind a large area of woodland. Given the screening provided by the woodland and the distance from the carriageway there will be no impact on the building‟s setting. BH 35 & 36 / 6.1 Whitewebbs Farmhouse, a Medium The buildings are c. 475m south of the carriageway. No change Neutral Sheet 4 two and a half storey red brick The nearest cantilever (GB48550) is located to the building and timber framed north of the farmhouse behind a screen of trees and barn, both Grade II Listed. will not be visible from the farmhouse. Cantilever GA48320 is on the opposite side of the carriageway, also screened from view. BH 43 / 6.1 Sheet 4 Theobalds Manor, Old Park Medium The house has attractive views to the south west but No change Neutral Ride is a large red brick house views of the carriageway are prevented by a large on a square plan with hipped area of woodland between the house and the mansard roof. It is Grade II carriageway. Listed.
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BH Ref / NMR No. / Outline description of Value Description of likely impact including potential Magnitude of Impact Significance of Figure Ref Designated Asset mitigation measures Effect BH 37 & 38 / 6.1 Bullscross Farmhouse, an 18th Medium The farmhouse has views to the east but limited No change Neutral Sheet 4 century house with five bay views to the south due to the orientation of the timber frame barn to the north. principal facade and thick tree cover immediately to Both are Grade II Listed the south of the building. The barn to the north is surrounded by large agricultural buildings. Views of new gantries will not be possible from the farm complex. BH 39 – 41 / 6.1 Theobalds Park Farmhouse, Medium The complex is located just off the Great Cambridge No change Neutral Sheet 4 the timber framed barn and dual carriageway c. 400m to the north of Junction thatched barn are all Grade II 25. Views from the farm complex are dominated by Listed. the immediate dual carriageway and the raised motorway junction which will obscure views of any new gantries.
Forty Hill Forty Hall Conservation Area High The majority of the Conservation Area, including No change Neutral Conservation Area contains three large country those parts which contain Forty Hall and Myddleton incl BH 26 – 31 / 6.1 estates: Forty Hall, Capel House are outside the study area. Capel Manor Sheet 4 Manor and Myddleton House complex, the northern most buildings in the and the sparsely settled areas Conservation Area and closest to the M25 include a of Forty Hill, Maiden‟s Cross stables, coach house and garden walls. Capel and Bulls Cross. The Manor is a large country house designed to take in Conservation Area includes 5 views to the south and north. The views to the north Listed Buildings within 500m are not far reaching and due to the extensive tree of the carriageway: The planting within the grounds and adjacent to the Orchards, Pied Bull Public motorway carriageway the estate feels very House, Bullscross Lodge – all enclosed, cut off from the surrounding area. Nearby Grade II and Capel Manor – proposed gantries (GAB49595, GA50005) will not be Grade I including garden walls visible. which are Grade II Listed. BH1 & BH 42 / 6.1 Eleanor Cross on the High High The medieval stone cross is located c. 400m to the No change Neutral Sheet 5 Street in Waltham Cross is north of the carriageway and Harold House is c. both Grade I Listed and 250m to the north. Directly to the south, the M25 Scheduled. Just to the south is carriageway is within a tunnel, and emerges just to Harold House, also on the the east. The area is very built up surrounding the High Street. cross and Harold House and so the extensive development would screen proposals in this area.
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BH Ref / NMR No. / Outline description of Value Description of likely impact including potential Magnitude of Impact Significance of Figure Ref Designated Asset mitigation measures Effect BH 33 / 6.1 Sheet 5 Canal Bridge at Ramey Lock Medium The bridge is located 300m to the south of the No change Neutral is Grade II Listed. carriageway and south east of GB52860. The bridge is screened to the north west by trees along the canal. Waltham Abbey The historic centre of Waltham High Only the very southern part of the Waltham Abbey No change Neutral Conservation Area / Abbey formed around the Conservation Area is within 500m of the 6.1 Sheet 5 Abbey Church. carriageway. There is a large amount of intervening development between the Conservation Area and the carriageway so proposed new gantries will be screened from view. BH 21, 22 & 68 / 6.1 Thrift Cottage, Essex House High There is a large amount of intervening development No change Neutral Sheet 5 and Thrift Hall are all on the including a large industrial estate and woodland Sewardstone Road. Essex between the buildings and the carriageway so House is Grade II* Listed, the proposed new gantries will be screened from view. other two are Grade II Listed. BH 64 / 6.1 Sheet 6 The Lodge for Upshire Hall on Medium The Lodge is 75m from the carriageway, which is No change Neutral Honey Lane is Grade II Listed. running along an embankment at this location. The carriageway is a very dominating presence in the views from the Lodge. GB56550 is the nearest cantilever (c. 250m to the east of the Lodge), and this will be placed on the far side of the motorway where it will be out of view. Cantilever GA55800 is located c. 300m to the west of the Lodge and although it may be visible, the intervening development, height of the carriageway at this point and the dominating presence of the motorway will not alter the current setting of the Lodge. BH 20 & 23 / 6.1 Upshire Hall is a large red Medium Upshire Hall is designed to take in views to the south No change Neutral Sheet 6 brick 18th century house, now where the carriageway is located. The farmhouse is converted into a hotel complex further to the north, set within a series of industrial with modern additions. To the and agricultural buildings. There is a thick line of north is Southend Farmhouse. trees planted to screen views of the carriageway. Both are Grade II Listed GB56550 on the far side of the carriageway will not be visible. GAB56875 will be screened from view by trees.
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BH Ref / NMR No. / Outline description of Value Description of likely impact including potential Magnitude of Impact Significance of Figure Ref Designated Asset mitigation measures Effect Upshire Upshire Conservation Area is Medium The large majority of the Conservation Area is Negligible Neutral Conservation Area a large portion of rural land outside of the study area, including Warlies park. incl BH 25 & 24/ 6.1 with only a small southern Two hamlets - Copthall Green and Wood Green - Sheet 6 section being located within are within the study area with their linear settlements the study area. The abutting the carriageway. At the end of Woodgreen Conservation Area includes Road thick tree coverage blocks views from the large parkland estate of Woodgreen Farmhouse and more sensitive areas of Warlies and a number of small the Conservation Area towards the new gantry hamlets. At the southern end GAB58675. of Woodgreen Road is Grade At the southern end of Copthall Green Lane there is II Listed Woodgreen less planting and the motorway is in prime view. A Farmhouse and at the new gantry is proposed just to the west of Copthall southern end of Copthall Lane underbridge (GAB58070) and glimpses may be Green Lane is Grade II Listed possible from along the Lane heading south where a Raveners Farmhouse. number of unlisted dwellings and Raverners The Upshire Conservation Farmhouse are located. Such glimpsed views will Area is directly adjoined by the not further detract from the setting of the Farmhouse. Copped Hall Park Onsite planting around the new gantry would Conservation Area. enhance current views. Copped Hall The Registered Park (Grade High Views of the carriageway are prevented from the Negligible Slight Adverse Registered Park and II*) and Conservation Area of southern and northern side of the Park from CH Garden including BH Copped Hall cover a large 58200 eastwards due to the thick woodland within 19 / 6.1 Sheet 7 area encompassing Copped „The Warren‟. In addition the motorway is in a slight Hall itself c. 700m to the north cutting at this point. East of the Warren Bridge over of the carriageway and a large bridge, intermittent views of the motorway are area of woodland known as possible when looking from the Hall to the south and The Warren to the south of the east. carriageway. The Warren wooded area also includes the There will be a new gantry (GAB56740) and new Grade II* listed lodges at the cantilever (GB58645) in the area of the Warren. southern end of the park (BH 19) . The land rises quite significantly to the north where There will be a new cantilever at GB59045 and Copped Hall is located and adapted gantry at GA59505, south of Copped Hall. there are long reaching views Both of these are well screened by on and offsite to the west of Copped Hall planting. with designed gardens to take
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BH Ref / NMR No. / Outline description of Value Description of likely impact including potential Magnitude of Impact Significance of Figure Ref Designated Asset mitigation measures Effect advantage of this view. The In addition, a new gantry is proposed c. 250m to the Registered Park boundary east of the Registered Park (within the Conservation crosses the M25 carriageway Area) (GAB59880). Glimpses of this sign may be itself. possible from the higher ground within the park particularly from the lane running south from the Hall. As described this is not the principal designed vista but it would increase the presence of the road slightly from views within the park. Planting here should be retained and enhanced to screen views from the hall. These glimpses will only very slightly change the existing views within the park, and will be barely perceptible. In terms of traffic changes, there is only a 10% increase expected in traffic at Design Year (2015) which traffic changing from c. 163,000 AADT flow to c. 180,000 AADT. This slight increase will not degrade the ambiance or character of the park. Copped Hall Park The Conservation Area of High As above, for Copped Hall Park RPG: Negligible Slight Adverse Conservation Area Copped Hall covers the and BH 19, 3 & 4 / Registered Park and a large There will be a new gantry (GAB56740) and new 6.1 Sheet 7 area extending further to the cantilever (GB58645) in the area of the Warren. west and east and incorporating two Grade II Listed houses along High There will be a new cantilever at GB59045 and Road (Park Cottage and adapted gantry at GA59505, south of Copped Hall. House south of Park Cottage Both of these are well screened by on and offsite – BH 3 & 4) planting.
In addition, a new gantry is proposed c. 250m to the east of the Registered Park (within the Conservation Area) (GAB59880). Glimpses of this sign may be possible from the higher ground within the park particularly from the lane running south from the Hall. As described this is not the principal designed vista but it would increase the presence of the road slightly. Planting here should be retained and
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BH Ref / NMR No. / Outline description of Value Description of likely impact including potential Magnitude of Impact Significance of Figure Ref Designated Asset mitigation measures Effect enhanced to screen views from the hall.
In terms of traffic changes, there is only a 10% increase expected in traffic at Design Year (2015) which traffic changing from c. 160,000 AADT flow to c. 180,000 AADT. This slight increase will not degrade the ambiance or character of the Conservation Area.
At the very south eastern extent of the Conservation Area are two Listed houses (BH 3&4) where a new cantilever sign is proposed on the opposite side of the carriageway (GA60160) and an existing cantilever sign is to be modified (GA60360). These houses are located behind an area of thick woodland and so there will be no views of the gantries at this location.
A11 / 6.1 Sheet 7 Ambresbury Banks Hillfort is a High This site is in thick woodland with no views of the No change Neutral Scheduled Monument c. 400m motorway. to the south of the carriageway and is surrounded by thick planting. Bell Common Bell Common Conservation Medium The proposals either side of the tunnel involve the No change Neutral Conservation Area Area including the Grade II modification of existing signs. There will be no incl. BH2, 5-7) / 6.1 Listed houses along Bell change to the setting of the Conservation Area or Sheet 7 Common and High Road. Bell Listed buildings. Common is a linear settlement running north east / south west and ending at the carriageway. The carriageway is within a tunnel to the south at this location with thick tree cover along the carriageway as it enters the tunnel.
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BH Ref / NMR No. / Outline description of Value Description of likely impact including potential Magnitude of Impact Significance of Figure Ref Designated Asset mitigation measures Effect BH 12 – 14 / 6.1 Coopersale Hall, Gardeners Medium The only proposal at this location involves the No change Neutral Sheet 8 Farmhouse and Barn to the removal of an existing gantry and construction of a north are all Grade II Listed. replacement c. 10m to the west. There will be no change to the existing setting of these Listed Buildings. BH 8 – 11 / 6.1 Garnish Hall, outbuilding and Medium The views from this location are dominated by the No change Neutral Sheet 8 timber framed barns to the M11 / M25 junction. No new gantries will be visible. rear – all are Grade II Listed and located c. 150m from M25 carriageway (only 50m to east of M11 / M25 junction).
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6.8 Significance of Effects on Plans and Policies
6.8.1 Overall there will be a very low level of impact on designated historic environment assets. There will not be total loss of or substantial harm to any assets, in line with National Planning Policy Framework Policy 12. The proposals do not contravene any other plans or policies relating to the historic environment. 6.9 Indication of Any Difficulties Encountered 6.9.1 It was not possible to gain access to all the historic environment assets within the study area - a small number of these were located behind gated private entrances. However it was possible to access nearby public footpaths or roads to enable important views and the setting of assets to be assessed. 6.9.2 Detailed information regarding predicted traffic levels and changes in noise and vibration is awaited. 6.9.3 The location of site compounds, haul roads and methods of construction is not known and cannot be assessed as part of these proposals. 6.9.4 Consultation has not yet been undertaken with the statutory authorities or relevant officers in the local planning authorities. 6.10 Recommendations 6.10.1 Mitigation measures, in the form of design improvements, have been taken into account in determining the significance of effects in the above table, on an asset by asset basis. The following is a summary of the design and mitigation proposals: 6.10.2 There should be onsite planting to reduce the visual impact of GB43300 and GA43160 on North Lodge (BH34) 6.10.3 There should be onsite planting to screen GB46100 from Paddocks Farmhouse and barns (BH55/56) 6.10.4 There should be enhanced screening at GAB58070, to screen views from Raveners Farmhouse (BH24) 6.10.5 Planting should be retained and enhanced at GAB59880 which is within the Copped Hall Registered Park and Garden, and Conservation Area. 6.10.6 The results of consultation will feed into these recommendations. 6.11 Summary 6.11.1 The proposals will have a slight adverse effect on three designated heritage assets: one Grade II Listed Building, one Conservation Area and one Grade II* Registered Park and Garden. However, the majority of the c. 55 designated heritage assets within the study area will not be affected by the proposals. 6.11.2 There will be no significant effects on any designated heritage assets as a result of the Project giving an overall assessment of slight adverse for cultural heritage.
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7. Landscape 7.1 Study Area 7.1.1 The Study Area for this landscape and visual assessment is shown on Figure 7.1. 7.1.2 The Study Area boundary is defined by the Visual Envelope, which shows the approximate extent of visibility of the Project. There are, however, areas within the Visual Envelope where there are no views of the Project due to the screening effect of vegetation, built elements and/or built form. 7.1.3 The Visual Envelope was ascertained following desk-based study and site survey work carried out in July 2011. 7.2 Baseline Conditions Landscape Designations 7.2.1 Landscape designations located within the Study Area are summarised below and illustrated on Figure 7.1. The regulatory and planning policy framework for these designations has been included in Section 7.5. Ancient Woodland 7.2.2 Ancient woodlands are woods that have been in existence since at least 1600 AD and have only been cleared for underwood or timber production. There are four ancient woodlands located within the Study Area: Pond Wood Oxleys Wood Epping-Ambresbury Banks Barbers Wood Conservation Areas 7.2.3 Conservation Areas are areas of special architectural or historic interest, the character or appearance of which it is desirable to preserve or enhance. There are seven Conservation Areas within the Study Area: The Royds Potters Bar Forty Hall Upshire Copped Hall Bell Common Coopersale Street Hill Hall Registered Historic Parks and Gardens 7.2.4 Since the 1980s there has been a national register of historic parks and gardens established and maintained by English Heritage. There are four registered historic parks and gardens within the Study Area: Myddleton House (Grade II) Copped Hall (Grade II*)
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Coopersale House (Grade II) Hill Hill (Grade II) Watling Chase Community Forest 7.2.5 Watling Chase Community Forest aims to regenerate and revitalise the green spaces in and around major towns and to create well-wooded environments for work, wildlife, recreation and education. 7.2.6 The western edge of the Study Area, around Potters Bar, is located within the Watling Chase Community Forest (refer to Figure 7.1). Lee Valley Regional Park 7.2.7 The Lee Valley Regional Park was established by Parliament in 1967 and was created to meet the recreation, leisure and nature conservation needs of London, Hertfordshire and Essex. 7.2.8 Lee Valley Regional Park is located within the Study Area, crossing the M25 between Junctions 25 and 26. Epping Forest 7.2.9 Epping Forest is about 12 miles long and 2.5 miles wide and is the largest public open space near London. The protection afforded by the Epping Forest Act 1878 has meant that a substantial area of the original ancient Forest of Essex remains virtually intact. 7.2.10 Epping Forest is located is close proximity to the Study Area between Junctions 26 and 27. Landscape Conservation Area 7.2.11 Landscape Conservation Areas have been identified by Hertsmere Borough Council and comprise „the most attractive areas of countryside‟ (Hertsmere Borough Council, 2003). 7.2.12 A Landscape Conservation Area is located within the Study Area, to the north west of Junction 23. Area of Special Character 7.2.13 Areas of Special Character have been identified by the London Borough of Enfield, in order to preserve and enhance their character (London Borough of Enfield, 1994). 7.2.14 There are two Areas of Special Character located within the Study Area: Enfield Chase Lee Valley Landscape Character 7.2.15 The existing landscape character of the Study Area is summarised below. The location of the regional and local landscape character areas are shown on Figure 7.2. National Landscape Character 7.2.16 All of the Study Area is within the Northern Thames Basin National Character Area (111), as identified by Natural England‟s National Character Areas Map (Natural England, 2005). 7.2.17 Key characteristics identified for Northern Thames Basin National Character Area (111) include: A diverse landscape with a series of broad valleys containing the major rivers Ver, Colne and Lea and extensive areas of broadleaved woodlands being the principal features of the area. The landform is varied with a wide plateau divided by the valleys. Hertfordshire‟s large towns, the M25 and M1 motorways, railway line and prominent electricity pylons are also a major influence on character.
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Floodplain land is commonly arable sub-divided by hedgerow-deficient field boundaries. Open grazing land remains in certain areas. Regional Landscape Character 7.2.18 Published regional Landscape Character Areas within the Study Area (Hertfordshire County Council, 2001 & Essex Landscape Character Assessment, 2003) are summarised below and illustrated on Figure 7.2. There is currently no published landscape character assessment for Greater London Authority/London Borough of Enfield located within the Study Area. Hertfordshire Landscape Character Areas 21: High Canons Valleys and Ridges 7.2.19 Key characteristics include: A series of narrow settled ridges of sinuous form. Slopes to the south east comprise mainly medium to large arable fields and more open character. Slopes to the west and north east comprise a more intact landscape of small/medium pasture and numerous field oaks. Woodland blocks and copses scattered throughout the area. 24: Arkley Plain 7.2.20 Key characteristics include: Gently undulating plain. Extensive areas of equestrian activity and grazing. Medium arable fields to the north with hedges and field trees in a declining condition. Major motorway, trunk road and associated infrastructure. 25: Wrotham Park and Bentley Heath 7.2.21 Key characteristics include: Level plateau area. Historic parkland of Wrotham Park with perimeter tree belts. Small fields of pasture associated with Bentley Heath. Straight roads and wide verges on perimeter of parkland. 26: Hornbeam Hills (Enfield Chase) 7.2.22 Key characteristics include: Geometric field pattern. Steeply sloping valley landforms. Sparsely settled. Sweeping views over landforms. Potters Bar and M25 to north west.. 27: Catherine Bourne Valley 7.2.23 Key characteristics include: Large-scale arable farmland with low and relic hedgerows. Long-distance views. Major transport corridors. Catherine Bourne stream.
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53: Northaw Common Parkland 7.2.24 Key characteristics include: Tight circles of Scots pine, limes and oaks planted in open parkland. Lodge houses and grand entrances to mansions. Restricted views and limited public access. Mixed architectural influences. 55: Theobalds Estate 7.2.25 Key characteristics include: Discrete woodlands and estate farmland. Undulating landform. Mansions and isolated farms. Transport infrastructure. Essex Landscape Character Assessment Areas C3: Lee Valley 7.2.26 Key characteristics include: Very broad, flood plain occupied by wet gravel pits, woodland and a variety of fragmented agricultural, recreational and small scale industrial land uses. Rolling farmland to the east, typically with bold blocks of woodland and linear tree belts on valley sides and ridges. Significant clusters of active and derelict glasshouse land use. Extensive views from higher ground within the area. D1: Epping Forest and Ridges 7.2.27 Key characteristics include: Elevated moderate to steep sided ridges, crowned by woodland. Very large crescent shaped block of ancient deciduous woodland to the west. Distinctive grassy plains and large ponds within Epping Forest, greens and commons associated with settlements. Small to medium scale pattern of hedged pasture and arable fields with frequent hedgerow trees. C4: Roding Valley 7.2.28 Key characteristics include: Wide valley, deepening to the south. Gently to moderately undulating valley sides, occasionally intersected by small tributary valleys. Strong pattern of valley side vegetation with thick hedgerow field boundaries, many hedgerow trees and scattered small woodlands. Meadows on flat valley floor, with occasional riverside trees. Local Landscape & Townscape Character 7.2.29 Local Landscape and Townscape Character Areas (L1 to L4) were identified following site survey work in July 2011. This was undertaken to cover areas within the Study Area where there was no
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existing published landscape character data, i.e. Greater London Authority / London Borough of Enfield. L1: Potters Bar 7.2.30 Key characteristics include: Low to medium density twentieth Century suburban estate developments. Area bisected in a north-south direction by the mainline railway. Mature garden vegetation and street trees provide a green framework to area. Open areas include allotments and cemeteries providing a green framework. L2: Holly Hill Farmland 7.2.31 Key characteristics include: Large to medium-scale farmland. Gently rolling topography. Mature oak trees along field boundaries and woodland copses. Isolated farmstead and residential properties scattered through area. L3: Whitewebbs Parkland 7.2.32 Key characteristics include: Recreation land, including golf courses and Country Park. Historic parkland associated with Myddelton House. Villages and individual farmsteads. Mature woodland vegetation. L4: Waltham Cross and North Enfield 7.2.33 Key characteristics include: Built urban area bisected by major A-roads and the M25. Large-scale twentieth Century industrial and commercial zones. High and medium density residential housing and flats (dating from the nineteenth and twentieth Century). Local shopping areas along major infrastructure routes. The Lee River and canal lies at the eastern edge of this character area. Visual Amenity Receptors 7.2.34 The Visual Impact Schedule (VIS) in Appendix F sets out all visual receptor groups within the Study Area and describes their existing views (refer to Figure 7.5). Visual receptor groups and their views are also summarised below: Properties 7.2.35 There are several properties and farmsteads surrounding countryside to the north and south of Junction 23 with distant views towards the M25 on embankment, including views of existing lighting columns, signage and moving traffic. 7.2.36 From the southern fringes of Potters Bar, as well as from some high rise buildings towards the centre of Potters Bar, there are some direct upper storey views of the M25 on embankment. Views occur to moving traffic and motorway infrastructure, where intervening vegetation allows. 7.2.37 Between Junction 24 and 25 there are several farmsteads and small settlements to the north and south of the M25 corridor with views towards the M25, including farmstead along the Ridgeway.
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Views are often filtered and screened by roadside and field vegetation, but some clear views occur to vehicle movements and infrastructure. 7.2.38 To the east of Junction 25 views from Waltham Cross and Bullsmoor are limited by Holmesdale Tunnel. However, there are some upper storey views, including views from Arlington Crescent, of high-sided vehicles and lighting columns. 7.2.39 Towards the southern fringes of Waltham Abbey settlement there are some views towards the M25. 7.2.40 A few properties at Wood Green and Copthall Green have views of moving traffic and signage where local topography and vegetation allows. 7.2.41 At Epping village, views are restricted by mature woodland vegetation and the Bell Common Tunnel. However there are some views towards the M25, from the south-eastern fringes of the settlement, where mature HA boundary vegetation allows. 7.2.42 The north-eastern edge of Theydon Bois has some distant views towards the M25 over rolling agricultural fields, including views of moving traffic and the M11 in the distance. 7.2.43 Surrounding Junction 27 there are several scattered properties and farmsteads with some upper storey views towards the M25 and M11 on embankment. Public Rights of Way 7.2.44 The most important public access routes, with views towards the M25 within the Study Area are four national trails described below. 7.2.45 Part of the Chain Walk national trail goes northwards from Crews Hill under the M25 and then continues northwards to Cuffley. Some clear views of M25 on embankment are afforded from this trail including moving traffic and lighting columns through breaks in vegetation. Another section of the Chain Walk national trail crosses over the M25 from Whitewebbs Lane heading northwards to Old Park Ride, providing clear open views along the M25 corridor. 7.2.46 Lee Valley Walk national trail crosses under the M25 between Enfield Lock and Holdbrook, along the River Lee. Views of the raised M25 on the bridge over the River Lee are afforded through breaks in riverside vegetation. 7.2.47 The Three Forests Way national trail crosses over the M25 between Woodredon House to the south and Upshire village to the north. Clear views to the M25 corridor occur from the motorway overbridge and several views to the M25 occur to the north of the overbridge where intervening vegetation and topography allows. 7.2.48 The Essex national trail through Epping Forest has no views to the M25 due to the forest vegetation and Bell Common tunnel. Open Space 7.2.49 There are numerous areas of open space between Junctions 23 and 27 with views towards the M25 including sports grounds, cemeteries, allotments and golf courses. The most important areas of public open space include the Lee Valley Regional Park and Epping Forest. 7.2.50 Views from the Lee Valley Regional Park to the M25 occur where intervening riverside vegetation allows. Views occur to the M25 bridge crossing the River Lee and associated lighting, signage and vehicular movement. 7.2.51 Views from Epping Forest are restricted by the mature woodland vegetation and Bell Common Tunnel together with the motorway being in cutting where it approaches the tunnel.
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Roads 7.2.52 Views from surrounding roads to the motorway are often restricted by intervening vegetation and topography. Clear views to the motorway occur where roads cross over the M25 on overbridges and at junctions. 7.2.53 The A1081, St Albans Road and A1000 Barnet Roads have some clear views to the M25 between Junctions 23 and 24, including views to existing lighting, gantries and vehicular movement. 7.2.54 The A10 Great Cambridge Road crosses the M25 at Junction 25, with views of lighting columns and high-sided moving traffic on the approach to Holmesdale Tunnel. 7.2.55 The A121 Honey Lane crosses the M25 and at Junction 26, resulting in clear views to vehicular movement and light columns from the road. 7.3 Methodology 7.3.1 This detailed level of assessment was undertaken in accordance with IAN 135/10. The assessment methodology used to determine the value (sensitivity) of resources, magnitude of impact (change) and significance of landscape and visual effects is set out below. Landscape Value (Sensitivity) of Resource 7.3.2 The sensitivity of landscape character areas, within the Study Area, was determined using the definitions set out in Table 7.1. Table 7.1 - Landscape Sensitivity and Typical Examples Sensitivity Typical Descriptors and Examples High Landscapes which by nature of their character would be unable to accommodate change of the type proposed. Typically these would be; - Of high quality with distinctive elements and features making a positive contribution to character and sense of place. - Likely to be designated, but the aspects which underpin such value may also be present outside designated areas, especially at the local scale. - Areas of special recognised value through use, perception or historic and cultural associations. - Likely to contain features and elements that are rare and could not be replaced. Moderate Landscapes which by nature of their character would be able to partly accommodate change of the type proposed. Typically these would be; - Comprised of commonplace elements and features creating generally unremarkable character but with some sense of place. - Locally designated, or their value may be expressed through non-statutory local publications. - Containing some features of value through use, perception or historic and cultural associations. - Likely to contain some features and elements that could not be replaced. Low Landscapes which by nature of their character would be able to accommodate change of the type proposed. Typically these would be; - Comprised of some features and elements that are discordant, derelict or in decline, resulting in indistinct character with little or no sense of place. - Not designated. - Containing few, if any, features of value through use, perception or historic and cultural associations. - Likely to contain few, if any, features and elements that could not be replaced.
Source: Based on IAN 135/10, Annex 1, Table 2, HA, 2010
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Magnitude of Impacts 7.3.3 The magnitude of landscape impacts for the Project has been determined based on the definitions set out in Table 7.2. Where night-time impacts are anticipated these have been described, together with the day-time impacts, and the overall magnitude of impact adjusted accordingly. Table 7.2 - Assigning Magnitude of Landscape Impacts Magnitude Typical Criteria Descriptors of Impact Major Total loss or large scale damage to existing character or distinctive features and Adverse elements, and/or the addition of new but uncharacteristic conspicuous features and elements. Moderate Partial loss or noticeable damage to existing character or distinctive features and Adverse elements, and/or the addition of new but uncharacteristic noticeable features and elements. Minor Slight loss or damage to existing character or features and elements, and/or the Adverse addition of new but uncharacteristic features and elements. Negligible Barely noticeable loss or damage to existing character or features and elements, Adverse and/or the addition of new but uncharacteristic features and elements. No Change No noticeable loss, damage or alteration to character or features or elements.
Negligible Barely noticeable improvement of character by the restoration of existing features and Beneficial elements, and/or the removal of uncharacteristic features and elements, or by the addition of new characteristic elements. Minor Slight improvement of character by the restoration of existing features and elements, Beneficial and/or the removal of uncharacteristic features and elements, or by the addition of new characteristic elements. Moderate Partial or noticeable improvement of character by the restoration of existing features Beneficial and elements, and/or the removal of uncharacteristic and noticeable features and elements, or by the addition of new characteristic features. Major Large scale improvement of character by the restoration of features and elements, Beneficial and/or the removal of uncharacteristic and conspicuous features and elements, or by the addition of new distinctive features.
Source: Based on IAN 135/10, Annex 1, Table 1, HA, 2010
Significance of Effects 7.3.4 The significance of landscape effects has been determined by examining the sensitivity of resources and magnitude of impact at Project opening (winter) and 15 years after opening (both winter and summer). 7.3.5 The significance of landscape effects has been formulated as a function of the resource sensitivity and the magnitude of Project impact. The following matrix was used to determine the significance of effect:
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Table 7.3 - Determining the Significance of Effect on Landscape Landscape Magnitude Of Impact Sensitivity No Change Negligible Minor Moderate Major High Neutral Slight Slight or Moderate or Large or Very Moderate Large Large Moderate Neutral Neutral or Slight Moderate Moderate or Slight Large Low Neutral Neutral or Neutral or Slight Slight or Slight Slight Moderate
Source: Based on IAN 135/10, Annex 1, Table 3, HA, 2010 7.3.6 Table 7.4 describes the typical descriptors of significance of effect for landscape as used in the assessment: Table 7.4 – Typical Descriptors of Significance of Effect Categories for Landscape Significance of Description Effect 1 The project would: Very Large - Greatly enhance the character (including quality and value) of the Beneficial landscape. (Positive) Effect - Create an iconic high quality feature and/or series of elements. - Enable a sense of place to be created or greatly enhanced. 2 The project would: Large Beneficial - Enhance the character (including quality and value) of the landscape. (Positive) Effect - Enable the restoration of characteristic features and elements lost as a result of changes from inappropriate management or development. - Enable a sense of place to be enhanced. 3 The project would: Moderate Beneficial - Improve the character (including quality and value) of the landscape. (Positive) Effect - Enable the restoration of characteristic features and elements partially lost or diminished as a result of changes from inappropriate management or development. - Enable a sense of place to be restored. 4 The project would: Slight Beneficial - Complement the character (including quality and value) of the landscape. (Positive) Effect - Maintain or enhance characteristic features and elements. - Enable some sense of place to be restored. 5 The project would: Neutral Effect - Maintain the character (including quality and value) of the landscape. - Blend in with characteristic features and elements. - Enable a sense of place to be retained. 6 The project would: Slight Adverse - Not quite fit the character (including quality and value) of the landscape. (Negative) Effect - Be at variance with characteristic features and elements. - Detract from a sense of place. 7 The project would: Moderate Adverse - Conflict with the character (including quality and value) of the landscape. (Negative) Effect - Have an adverse impact on characteristic features or elements. - Diminish a sense of place
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Significance of Description Effect 8 The project would: Large Adverse - Be at considerable variance with the character (including quality and (Negative) Effect value) of the landscape. - Degrade or diminish the integrity of a range of characteristic features and elements. - Damage a sense of place. 9 The project would: Very Large Adverse - Be at complete variance with the character (including quality and value) of (Negative) Effect the landscape. - Cause the integrity of characteristic features and elements to be lost. - Cause a sense of place to be lost.
Source: Based on IAN 135/10, Annex 1, Table 4, HA, 2010 Visual Effects Visual Sensitivity 7.3.7 The sensitivity of visual receptors, within the Study Area, was determined using the definitions set out in Table 7.5. Table 7.5 – Visual Sensitivity and Typical Descriptors Sensitivity Description High Residential properties. Users of Public Rights of Way or other recreational trails (e.g. National Trails, footpaths, bridleways etc.). Users of recreational facilities where the purpose of that recreation is enjoyment of the countryside (e.g. Country Parks, National Trust or other access land etc.). Moderate Outdoor workers. Users of scenic roads, railways or waterways or users of designated tourist routes. Schools and other institutional buildings, and their outdoor areas. Low Indoor workers. Users of main roads (e.g. trunk roads) or passengers in public transport on main arterial routes. Users of recreational facilities where the purpose of that recreation is not related to the view (e.g. sports facilities).
Source: Based on IAN 135/10, Annex 2, Table 1, HA, 2010 Magnitude of Impacts 7.3.8 The magnitude of visual impacts for the Project has been determined based on the definitions set out in Table 7.6. Where night-time impacts are anticipated these have been described, together with the day-time impacts and the overall magnitude of impact adjusted accordingly.
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Table 7.6 – Magnitude of Impact and Typical Descriptors Magnitude Typical Criteria Descriptors of Impact Major The project, or a part of it, would become the dominant feature or focal point of the view. Moderate The project, or a part of it, would form a noticeable feature or element of the view which is readily apparent to the receptor. Minor The project, or a part of it, would be perceptible but not alter the overall balance of features and elements that comprise the existing view. Negligible Only a very small part of the project would be discernable, or it is at such a distance that it would form a barely noticeable feature or element of the view. No Change No part of the project, or work or activity associated with it, is discernible.
Source: Based on IAN 135/10, Annex 2, Table 2, HA, 2010 Significance of Effects 7.3.9 The significance of visual effects has been determined by examining the sensitivity of receptors and magnitude of impact at Project opening (winter) and 15 years after opening (both winter and summer). 7.3.10 The significance of visual effects has been formulated as a function of the visual sensitivity and the magnitude of Project impact. The following matrix was used to determine the significance of effect: Table 7.7 - Determining the Significance of Effect on Visual Receptors Landscape Magnitude Of Impact Sensitivity No Change Negligible Minor Moderate Major High Neutral Slight Slight or Moderate or Large or Very Moderate Large Large Moderate Neutral Neutral or Slight Moderate Moderate or Slight Large Low Neutral Neutral or Neutral or Slight Slight or Slight Slight Moderate
Source: Based on IAN 135/10, Annex 2, Table 3, HA, 2010 7.3.11 Table 7.8 describes the typical descriptors of significance of effect for visual receptors as used in the assessment: Table 7.8 – Typical Descriptors of Significance of Effect Categories for Visual Receptors Significance of Description Effect Very Large Beneficial The project would create an iconic new feature that would greatly enhance the view. Large Beneficial The project would lead to a major improvement in a view from a highly sensitive receptor. Moderate Beneficial The proposals would cause obvious improvement to a view from a moderately sensitive receptor, or perceptible improvement to a view from a more sensitive receptor. Slight Beneficial The project would cause limited improvement to a view from a receptor of medium sensitivity, or would cause greater improvement to a view from a receptor of low sensitivity.
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Significance of Description Effect Neutral No perceptible change in the view. Slight Adverse The project would cause limited deterioration to a view from a receptor of medium sensitivity, or cause greater deterioration to a view from a receptor of low sensitivity. Moderate Adverse The project would cause obvious deterioration to a view from a moderately sensitive receptor, or perceptible damage to a view from a more sensitive receptor. Large Adverse The project would cause major deterioration to a view from a highly sensitive receptor, and would constitute a major discordant element in the view. Very Large Adverse The project would cause the loss of views from a highly sensitive receptor, and would constitute a dominant discordant feature in the view.
Source: Based on IAN 135/10, Annex 2, Table 4, HA, 2010 7.4 Value (Sensitivity) of Resource Landscape Sensitivity 7.4.1 Landscape sensitivity for each of the identified landscape character areas in Section 7.2, located within the Study Area, have been assessed based on the criteria set out in the methodology section (refer to Section 7.3,). 21: High Canons Valleys and Ridges 7.4.2 The area comprises medium arable fields and pasture land with numerous field oaks and woodland blocks and copses providing an intimate landscape. The area is located within the Watling Chase Community Forest. Landscape likely to tolerate a small degree of change (of the nature and type proposed) and effective mitigation would be possible. Sensitivity: Moderate. 24: Arkley Plain 7.4.3 This is an open and gently undulating character area of arable farmland, bisected by the M25. There are built and urban fringe influences including South Mimms service area. Field boundary vegetation, within this area, is often in a declining condition. The area is located within the Watling Chase Community Forest. Landscape likely to tolerate a large degree of change (of the nature and type proposed) and effective mitigation would be readily achievable. Sensitivity: Low. 25: Wrotham Park and Bentley Heath 7.4.4 This area is characterised by gently sloping, small fields and pasture associated with Bentley Heath. Wrotham Historic Park and Garden is located to the south beyond the Study Area boundary. The area is located within the Watling Chase Community Forest. The M25 corridor lies at the northern edge of this area and influences local character. Landscape likely to tolerate a small degree of change (of the nature and type proposed) and effective mitigation would be possible. Sensitivity: Moderate. 26: Hornbeam Hills (Enfield Chase) 7.4.5 This area is characterised by geometric arable land and some smaller pasture land. The area is bisected by M25 corridor and pylons cross the area. There are views towards Potter Bar to the north. The area is located within the Watling Chase Community Forest. Landscape likely to tolerate a large degree of change (of the nature and type proposed) and effective mitigation would be readily achievable. Sensitivity: Low.
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27: Catherine Bourne Valley 7.4.6 This area comprises large-scale arable farmland with low and relic hedgerows. Catherine Bourne Stream crosses through the area. The areas partly lies within the landscape conservation area (as designated by Hertsmere Borough Council, refer to Section 7. 2 and Figure 7.1) and within the Watling Chase Community Forest. Some views to the M25 occur. Landscape likely to tolerate a small degree of change (of the nature and type proposed) and effective mitigation would be possible. Sensitivity: Moderate. 53: Northaw Common Parkland 7.4.7 This area consists of mature woodland blocks and large-scale arable land. It is influenced by the M25 corridor on southern boundary and pylons cross this area. Pond Wood, ancient woodland is located in this area. Landscape likely to tolerate a large degree of change (of the nature and type proposed) and effective mitigation would be readily achievable. Sensitivity: Low. 55: Theobalds Estate 7.4.8 This area comprises an undulating landscape, with discrete woodland blocks and medium to large-scale arable farmland. The M25 corridor traverses this area. Landscape likely to tolerate a large degree of change (of the nature and type proposed) and effective mitigation would be readily achievable. Sensitivity: Low. C3: Lee Valley 7.4.9 This area consists of industrial land and residential housing at Waltham Cross, bisected by the M25 corridor. Lee Valley Regional Park and area of special character located to the western edge of this area. Towards the eastern edge of area, more woodland blocks (including Oxleys Wood, ancient woodland) and enclosed arable and pasture land. Upshire Conservation Area and part of Copped Hall historic park and garden are located in this area. Landscape likely to tolerate a small degree of change (of the nature and type proposed) and effective mitigation would be possible. Sensitivity: Moderate. D1: Epping Forest and Ridges 7.4.10 Area characterised by the ancient woodland of Epping Forest. The M25 corridor influence on the landscape is restricted, due to Bell Common Tunnel. Part of Copped Hall historic park and garden and Copped Hall Conservation Area lies within this character area. Epping village, including Bell Common Conservation Area, lies within this area. Griffins Wood and Epping-Ambresbury Banks ancient woodland located in this area. Coopersale House registered park and garden and Coopersale Street Conservation Area located at the north-eastern edge of this area. Landscape unlikely to tolerate much change (of the nature and type proposed) and effective mitigation would be difficult to achieve. Sensitivity: High. C4: Roding Valley 7.4.11 Open, undulating farmland and recreation land including golf courses. Scattered settlements, villages and farms through-out the area. The M25 corridor crosses through the centre of this area. Barber‟s Wood and Hill Springs, ancient woodland, are located within this area. Hill Hall historic park and garden and Hill Hall Conservation Area also lie at the eastern edge of this area. Landscape likely to tolerate a small degree of change (of the nature and type proposed) and effective mitigation would be possible. Sensitivity: Moderate. Local Landscape & Townscape Character L1: Potters Bar 7.4.12 This area comprises low to medium density twentieth Century suburban estate developments and includes a Conservation Area at The Royds, Potters Bar. The area is bisected in a north-south direction by the mainline railway. Views occur to the M25 corridor. Landscape likely to tolerate a
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small degree of change (of the nature and type proposed) and effective mitigation would be possible. Sensitivity: Moderate. L2: Holly Hill Farmland 7.4.13 This area is characterised by large to medium-scale farmland with gently rolling topography. Mature oak trees occur along field boundaries and woodland copses are common. This area lies within an area of special character. Views towards the M25 corridor occur. Landscape likely to tolerate a small degree of change (of the nature and type proposed) and effective mitigation would be possible. Sensitivity: Moderate. L3: Whitewebbs Parkland 7.4.14 The area is characterised by recreation land, including golf courses and country parks. The western edge of this area includes the registered historic park and garden of Myddelton House and Forty Hall Conservation Area. This area lies within an area of special character. Views occur towards the M25 corridor. Landscape likely to tolerate a small degree of change (of the nature and type proposed) and effective mitigation would be possible. Sensitivity: Moderate. L4: Waltham Cross and North Enfield 7.4.15 This area is characterised by a built urban landscape bisected by major A-roads and the M25. Large-scale 20th Century industrial and commercial zones occur, including high and medium- density residential properties. Landscape likely to tolerate a large degree of change (of the nature and type proposed) and effective mitigation would be readily achievable. Sensitivity: Low. Visual Receptor Sensitivity 7.4.16 Visual receptor sensitivity has been identified based on the criteria set out in the methodology section (refer to Section 7.3). 7.4.17 The Visual Impact Schedule sets out the sensitivity for all visual receptors potentially affected by the Project (refer to Appendix F Visual Impact Schedule). 7.5 Regulatory/Policy Framework 7.5.1 A summary of relevant national, county and district/borough level landscape policies, applicable to landscape designations within the Study Area, are summarised below. Policies have been included based on the location of landscape designations within the Study Area. For policies relating to Conservation Areas reference should be made to Chapter 6, the Heritage section of this report. With regard to relevant policies contained with regional spatial strategy, the East Oof England Plan, this is included in the chapter whilst a final decision is made on the revocation of RSSs however, given the Government‟s commitment, it is assumed that RSSs will no longer form part of the development plan for the purposes of determining planning applications. Ancient Woodland 7.5.2 Ancient woodland is a non-statutory designation. Ancient woodland is formally defined on maps by Natural England, and is given a degree of administrative protection through county and local planning policy. 7.5.3 The London Plan Consolidated with Alterations since 2004 (2008) does not have policies relating to ancient woodland but Policy 3D.15 Trees and woodland states that: “The Mayor will and boroughs should protect, maintain and enhance trees and woodland in support of the London Tree and Woodland Framework”
7.5.4 The London Plan (Greater London Authority, 2011) does not have policies relating to ancient woodland but Policy 7.21 states that:
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“ Trees and woodlands should be protected, maintained, and enhanced, following the guidance of the London Tree and Woodland Framework (or any successor strategy). In collaboration with the Forestry Commission the Mayor will produce supplementary guidance on Tree Strategies to guide each borough‟s production of a Tree Strategy covering the audit, protection, planting and management of trees and woodland. This should be linked to the borough‟s Open Space Strategy.”
7.5.5 Welwyn Hatfield District Plan (Welwyn Hatfield Borough Council, 2005) does not have any specific policy relating to ancient woodland however Policy R17 – Trees, Woodland and Hedgerows states: “The Council will seek the protection and retention of existing trees, hedgerows and woodland by the use of planning conditions, section 106 agreements, hedgerow retention notices and tree preservation orders where applicable. New development will be required to incorporate wherever appropriate new planting with locally native species….” 7.5.6 The Epping Forest District Plan (Epping Forest District Council, 2008) does not have any specific policy relating to ancient woodland, however Policy NC4 – Protection of Established Habitat states: “Development proposals will be expected to make adequate provision for the protection, enhancement and suitable management of established habitats of local significance for wildlife. Such provision may be more stringent when there are known to be protected species either on the site or likely to be affected by the development.” 7.5.7 Broxbourne Local Plan does not have a specific policy relating to ancient woodland however Policy H18 Trees, Hedges and Woodlands states that: “Before the council will grant consent for felling, topping or lopping of protected trees or removal of protected hedgerows, it will be necessary to demonstrate that: - (a) The tree(s) or hedgerow(s) is/are diseased and in need of work on public safety and/or environmental grounds; and/or (b) Removal of the tree(s) or hedgerows(s) is essential for the proper development of a site. When consent is granted for the removal of protected tree(s) or hedgerow(s) it will be accompanied by a requirement to undertake replacement planting. Replacement planting should be of an equivalent biomass, in a suitable location, and in sympathy with local landscape character (as assessed via a process of landscape character assessment. Any works which are authorised or required by the council to protect or replace trees or hedgerow(s) should be undertaken in accordance with good arboricultural practice.” Registered Historic Parks and Gardens 7.5.8 Registered historic parks and gardens are a non-statutory designation. The register is managed by English Heritage. Registered historic parks and gardens are given a degree of administrative protection through regional, county and local planning policy. 7.5.9 The East of England Plan (GOEE, 2008) Policy Env 6 The Historic Environment states: “In their plans, policies, programmes and proposals local planning authorities and other agencies should identify, protect, conserve and, where appropriate, enhance the historic environment of the region, its archaeology, historic buildings, places and landscapes, including historic parks and gardens and those features and sites (and their settings) especially significant in the East of England…” 7.5.10 The London Plan (Greater London Authority, 2011) Policy 7.8 Heritage Assets and Archaeology states:
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“Development affecting heritage assets and their settings should conserve their significance, by being sympathetic to their form, scale, materials and architectural detail.” 7.5.11 Epping Forest District Plan (Epping Forest District Council, 2008) Policy HC3 – Registered Parkland states: “The Council will not grant planning permission for development which could adversely affect the areas of registered parkland (identified as such on the Proposals Map).” 7.5.12 Broxbourne Local Plan 2005 Policy HD9 Parks and Gardens of Historic Interest states that: “Planning permission will not normally be granted for development which would have an adverse effect on the character and setting of an historic park or garden. The council will encourage retention and, where appropriate, restoration of any historic park or garden within the borough.” Watling Chase Community Forest 7.5.13 Watling Chase Community Forest is a non-statutory designation given a degree of administrative protection through regional, county and local planning policy. 7.5.14 The East of England Plan (GOEE, 2008) Policy ENV1: Green Infrastructure states: “Areas and networks of green infrastructure should be identified, created, protected, enhanced and managed to ensure an improved and healthy environment is available for present and future communities… Assets of regional significance for the retention, provision and enhancement of green infrastructure include:… other areas of landscape, ecological and recreational importance, notably the Community Forests (Thames Chase, Marston Vale and Watling Chase)….” 7.5.15 Hertsmere Borough Local Plan (Hertsmere Borough Council, 2003) Policy C7: Watling Chase Community Forest states: “The Watling Chase Community Forest Plan and any supplementary planning guidance to develop its themes will be a material consideration in the determination of planning applications in the Forest area when the principal aims of the Forest Plan will be taken into account. It will also provide the framework for formulating and implementing projects in partnership with other organisations such as the Countryside Management Service and Groundwork Hertfordshire.” 7.5.16 Hertsmere Revised Core Strategy (2010) Policy CS14 – Promoting Recreational and Access to Open Spaces and the Countryside states that: “The Council will work with its partners and relevant agencies to safeguard, enhance and facilitate access to parks, open spaces and to the local countryside. Measures which secure the provision of safer and more secure car-free access including enhancements and additions to the rights of way / Greenways network as set out in the Council‟s Greenways Strategy, will be actively sought where they do not present a risk to the biodiversity value and intrinsic environmental quality of the locality. The provision or enhancement of visitor and appropriate facilities in the countryside, including Watling Chase Community Forest Gateway Sites and Historic Parks and Gardens, will be encouraged where this: i) specifically enhances access for the local population ii) does not harm the character, appearance and openness of the Green Belt, landscape and wider countryside; iii) does not cause new road congestion; iv) does not exacerbate existing road congestion; and v) promotes uses which can be considered as appropriate in The Green Belt
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vi) will ensure that biodiversity is protected and enhanced in accordance with Policy CS12”. Lee Valley Regional Park 7.5.17 Regional Parks are a non-statutory designation, given administrative protection through county and local planning policy: 7.5.18 The East of England Plan (GOEE, 2008) Policy ENV1: Green Infrastructure states: “Areas and networks of green infrastructure should be identified, created, protected, enhanced and managed to ensure an improved and healthy environment is available for present and future communities… Assets of regional significance for the retention, provision and enhancement of green infrastructure include:… other areas of landscape, ecological and recreational importance, notably … the Lee Valley Regional Park….” 7.5.19 The London Plan (Greater London Authority, 2011) does not have a specific policy relating to Regional Parks, however Policy 2.18: Green infrastructure: the network of open and green spaces states: “The Mayor will pursue the delivery of green infrastructure by working in partnership with all relevant bodies, including across London‟s boundaries, as with the Green Arc Partnerships and Lee Valley Regional Park Authority. The Mayor will publish supplementary guidance on the All London Green Grid to apply the principles of the East London Green Grid to green infrastructure across London.” 7.5.20 Borough of Broxbourne Local Plan (Borough of Broxbourne, 2005) Policy CLT4: Lee Valley Regional Park states: “The Borough Council supports the Lee Valley Regional Park Authority in the continuing development of the Regional Park in the expectation that development will be predominantly recreational uses appropriate to a Regional Park. Some essential intensive recreational uses, still appropriate in the park, may be acceptable if it can be demonstrated that such uses cannot be accommodated in the urban area due to extensive land requirements and that such uses would fit with the overall provision of leisure and sporting facilities within the Borough.” 7.5.21 Borough of Broxbourne Submission Core Strategy 2010 Policy CS8 Environment states that... “The following green corridors will be protected and enhanced to help link open spaces in towns with surrounding countryside: the Lee Valley Regional Park, New River green chain, Spital Brook valley between Barclay Park and Hoddesdon Park Woods, Rags Brook valley between Rosedale and Cheshunt Common, Cheshunt Park, Wormley playing fields and land from Cedars Park into Theobalds Park. The Council will work with Lee Valley Regional Park Authority to deliver the visions, aims and objectives of the Park Plan 2000 and Park Development Framework” 7.5.22 The London Borough of Enfield Core Strategy (2010) Policy 34 Parks, playing fields, and other open spaces states that: “The Council will protect and enhance existing open space and seek opportunities to improve the provision of good quality and accessible open space in the Borough by...: ...Requiring the creation of new open space at Central Leeside as part of the regeneration of Meridian Water and which provides effective links to the Lee Valley Regional Park to the north and south” 7.5.23 Policy 35 Lee Valley Regional Park and Waterways. States that: “The Council will work with the Lee Valley Regional Park Authority, British Waterways, riparian owners, the Environment Agency and other partners to:
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Improve access to the Lee Valley Regional Park, particularly from residential communities to the west of the park, focusing on two key areas: Ponders End and Central Leeside. The area action plans will propose specific physical infrastructure and/or urban design in order to deliver improved access in these locations; Support the work of the Lee Valley Regional Park Authority (LVRPA) to realise the potential of the Lee Valley Regional Park. The Park Development Framework being prepared by the LVRPA will inform the preparation of the North East Enfield Area Action Plan, Central Leeside Area Action Plan and evidence base for review of the Core Strategy; and Make the best use of the waterway network (part of London's Blue Ribbon Network) in the Upper Lee Valley, including the River Lee, River Lee Navigation, and the Turkey, Salmons and Pymmes Brooks, seeking to fully restore the waterways and improve their pathways, and facilities for freight, recreational and educational use.” 7.5.24 Epping Forest District Plan (Epping Forest District Council, 2008) Policy RST24 – Design and Location of Development in the LVRP states: “All developments within or adjacent to the Lee Valley Regional Park should:- (i) have regard to the importance of the Park for leisure, recreation and nature conservation and make provision, where appropriate, for improved public access and landscaping; (ii) safeguard the amenity and future development of the Park; and (iii) conserve and, where possible, enhance the landscape of the Park or its setting. Developments which are likely to result in a significant adverse impact upon the character or function of the Park will not be permitted.” Epping Forest 7.5.25 The East of England Plan (GOEE, 2008) Policy ENV1: Green Infrastructure states: “Areas and networks of green infrastructure should be identified, created, protected, enhanced and managed to ensure an improved and healthy environment is available for present and future communities… Assets of regional significance for the retention, provision and enhancement of green infrastructure include:… other areas of landscape, ecological and recreational importance, notably … Epping Forest….” 7.5.26 The Epping Forest Act 1878 was passed saving the forest from enclosure. Epping Forest ceased to be a royal forest and was placed in the care of the City of London Corporation who act as 'Conservators'. The Epping Forest Act laid down a stipulation that the Conservators "shall at all times keep Epping Forest unenclosed and unbuilt on as an open space for the recreation and enjoyment of the people". 7.5.27 Epping Forest District Plan (Epping Forest District Council, 2008) Policy HC5 – Epping Forest states: “The Council will not grant planning permission for any development or use which could prejudice the historic nature and wildlife value of Epping Forest (identified on the Proposals Map) or its function as open space for the purposes of public enjoyment.” Landscape Conservation Area 7.5.28 Landscape Conservation Areas are a non-statutory designation, which has been identified at a local level by Hertsmere Borough Council. Hertsmere Borough Local Plan (Hertsmere Borough Council, 2003) Policy C9 Landscape Conservation Areas states:
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“Proposals within the Landscape Conservation Areas, as shown on the Proposals Map, will only be permitted if they are designed to a high standard, paying particular regard to the setting, siting, design and external appearance of the proposed development.” Area of Special Character 7.5.29 The London Borough of Enfield Core Strategy (2010) Policy 31 Built and landscape heritage states that the councils will be: “Ensuring that built development and interventions in the public realm that impact on heritage assets have regard to their special character and are based on an understanding of their context. Proposals within or affecting the setting of heritage assets will be required to include a thorough site analysis and character appraisal which explicitly demonstrates how the proposal will respect and enhance the asset.” 7.6 Design, Mitigation and Enhancement Measures 7.6.1 An iterative approach to Project design has been undertaken, taking account of the findings and recommendations of the Stage 2 Environmental Assessment Report simple level landscape and visual assessment. The current Project proposals are the result of a collaborative study by engineers and environmental specialists during design development of the project.. The current design as assessed in this Stage 3 report represents the optimum outcome taking account of multi-disciplinary factors. Some adverse landscape and visual effects are consequently unavoidable but are mitigated where possible. However, the Project is subject to ongoing design development which will review the mitigation proposed in this section of the report. Consideration will also be given to landscape enhancement measures where this is possible during the detail design stage. 7.6.2 Landscape mitigation measures are proposed wherever possible for sites where moderate or greater adverse effects have been identified at Year 15. Table 7.9 identifies receptors with anticipated moderate or greater adverse effects resulting from the Project at Years 1 and 15. The residual effects, i.e. assuming this mitigation is undertaken, are also identified. Table 7.9 - Proposed Mitigation and Residual Effects Receptor Significance of Recommended Mitigation Residual Impact Effect at Year 1 Year 1 (and Year & 15 15 if different) P3a: The Mimms Large Adverse Strengthen planting on off-slip Year 1: Caravan Park, embankment to provide partial screen Moderate Adverse South Mimms to new gantry. Available space limits Year 15: amount of planting achievable. Unlikely to be able to provide dense Slight Adverse and tall block of planting to achieve full screening of gantry from whole of site. P45: Skillet Hill Large Adverse Existing embankment already well Moderate Adverse Farm and The planted so insufficient space to Lodge, Waltham strengthen. Review potential to move Abbey gantry short distance further east to align with end elevation of main property, which would have less direct views than current position and would reduce night-time impacts of gantry lighting. Review potential for off-site planting. P8: Dame Alice Moderate Adverse Strengthen planting on clockwise Year 1: Owen School, embankment for at least 500m either Moderate Adverse Potters Bar side of Baker Street underbridge. Year 15:
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Receptor Significance of Recommended Mitigation Residual Impact Effect at Year 1 Year 1 (and Year & 15 15 if different) Slight adverse P12a: The Moderate Adverse (Limited or no opportunity for Moderate Adverse Gables and mitigation due to elevated road Preston Grange, position and already dense planting Ganwick Corner providing maximum possible screening.) P13: Dove Lane Moderate Adverse Strengthen planting on clockwise Year 1: & Byers Close, cutting between Caravan Site and Moderate Adverse Potters Bar alignment with Dove Lane. Year 15: Slight adverse P13a: Barnet Moderate Adverse (Limited or no opportunity for Moderate Adverse Road Caravan mitigation due to close proximity of Site gantry to site, already dense planting and presence of overhead power lines.) P17: Residential Moderate Adverse (Limited or no opportunity for on-site Year 1: and prep school mitigation planting due to lack of Moderate Adverse properties at available space.) Year 15: New Cottage/St Review potential for localised off-site Slight adverse John's Prep planting along field boundary at gantry School location. P19: Holly Hill Moderate Adverse Strengthen planting along anti- Year 1: Farm clockwise embankment, either locally Moderate Adverse around gantry sites or as a more Year 15: continuous belt of planting to provide an effective screen from the Project Slight adverse and the M25. P20: Properties Moderate Adverse Strengthen planting along clockwise Year 1: on Cattlegate cutting between Holly Hill Farm Moderate Adverse Road overbridge up to existing woodland Year 15: belt close to Cattlegate Road underbridge, either locally around Slight adverse gantry sites or as a more continuous belt of planting to provide an effective screen from the Project and the M25. P43: Beechfield Moderate Adverse Review potential to move ERA away Slight Adverse Walk and Lodge from residential area so clearance on Lane, Waltham dense planting belt can be reduced. Abbey P46: Property Moderate Adverse Strengthen planting along anti- Year 1: adjacent to clockwise carriageway locally to gantry Moderate Adverse Poplar Shaw, site. Large verge depth will allow Year 15: Waltham Abbey substantial planting plot. Mixed species will provide good year round Slight adverse screen. P48: Sudbury Moderate Adverse (Limited or no opportunity for Moderate Adverse Farm Caravan mitigation due to already dense Park and planting providing maximum possible Woodgreen screening.) Road P49: Southend Moderate Adverse (Limited or no opportunity for Moderate Adverse Lane and mitigation due to elevated road Woodgreen position and already dense planting
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Receptor Significance of Recommended Mitigation Residual Impact Effect at Year 1 Year 1 (and Year & 15 15 if different) Road providing maximum possible screening.) F9: Footpath Moderate Adverse Strengthen planting locally around Year 1: from Coopers gantry sites along anti-clockwise Moderate Adverse Lane Road to carriageway to screen views from Year 15: The Ridgeway, southern approach. via Holly Farm Slight adverse F10: Cattlegate Moderate Adverse (Limited or no opportunity for Moderate Adverse Footpath mitigation due to elevated road position and aspect of footpath in direction of gantry.)
7.6.3 The assessment has been undertaken with the assumption that the scheme will be designed to maximise the retention of existing planting. The requirement for mitigation planting has been highlighted in the Visual Impact Schedules but not included in the assessment as it is not clear based on working area of 6m for gantry construction and 8m for ERA if there would be space for planting within the highway boundary post construction. 7.6.4 Where Slight Adverse effects have been identified at Year 15 for other receptors, suitable mitigation measures will be included where appropriate and possible, to enhance the subsequent design of the Project. It is also assumed that best practice will be followed throughout, including: Ensuring loss of vegetation is minimised through good construction practices. Ensure protection of retained vegetation within the boundary in accordance with best practice and BS: 5837. Ensure all woodland adjacent to the highway boundary, including any ancient woodland, is protected in accordance with BS: 5837. 7.7 Magnitude of Impacts (Change) Landscape Impacts 7.7.1 The landscape magnitude of impact for each of the identified landscape character areas in Section 7.2 has been assessed for Year 1 (and Year 15 if different) based on the criteria set out in the methodology section (refer to Section 7.3, Table 7.3). 21: High Canons Valleys and Ridges 7.7.2 This area lies approximately 500 metres from the Project limit, to the south-west of Junction 23. No impact on the Watling Chase Community Forest is anticipated from the Project. No observable adverse or beneficial impacts from the Project would occur for this area. Magnitude of Impact: No Change. 24: Arkley Plain 7.7.3 This area includes Junction 23 and lies to the north and south of the M25 immediately east of Junction 23. Gantries, cantilever signs and ERAs are proposed in this area which would result in a very minor loss of mature vegetation within the Highway Boundary. No impact on the Watling Chase Community Forest is anticipated. A very minor loss to landscape elements would occur. Magnitude of Impact: Negligible Adverse. 25: Wrotham Park and Bentley Heath 7.7.4 This area lies to the south of the M25 between Junction 23 and 24. New gantries, cantilever signs and ERAs are proposed at the northern edge of this area, which would result in a minor loss of
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existing motorway soft estate. No impact on the Watling Chase Community Forest is anticipated. A very minor loss to landscape features is anticipated for this area. Magnitude of Impact: Negligible Adverse. 26: Hornbeam Hills (Enfield Chase) 7.7.5 This area crosses the M25 to the west of Junction 24. New signal and ADS gantry signs, ERAs and proposed nosing on the approach to Junction 24 would result in some very localised vegetation loss within the soft estate. No impact on the Watling Chase Community Forest is anticipated. Magnitude of Impact: Negligible Adverse. 27: Catherine Bourne Valley 7.7.6 This area lies a minimum of 250 metres to the north of Junction 23. No impacts on the designated landscape conservation area would occur, due to intervening distance and vegetation. No impact on the Watling Chase Community Forest is anticipated. No observable adverse or beneficial impacts from the Project are anticipated. Magnitude of Impact: No Change. 53: Northaw Common Parkland 7.7.7 This area lies immediately to the north of the M25 and to the east of Junction 24. There would be no impact on Pond Wood ancient woodland, which is located 100 metres to the north of the M25 highway boundary. New signal and ADS gantries and ERAs are proposed within the highway boundary at the southern edge of this area. This would result in a very minor loss of existing landscape features, i.e. mature vegetation within the soft estate. Magnitude of Impact: Negligible Adverse. 55: Theobalds Estate 7.7.8 This area crosses the M25 to the west of Junction 25. The Project includes new cantilever and gantry signals and ERAs, resulting in the loss of some mature vegetation within the soft estate and an increase in the number of lit elements along the motorway. A very minor loss of existing landscape elements anticipated. Magnitude of Impact: Negligible Adverse. C3: Lee Valley 7.7.9 This area lies to the north and south of the M25 at Junction 26. The Project would include new nosing, gantry and cantilever signs and ERAs, resulting in localised vegetation loss within the soft estate. A very minor change to the Lee Valley Regional Park character and area of special character are anticipated, due to direct proximity to the project, including lit matrix signs, however these changes would be seen in the context of the existing M25 corridor. Very minor impacts on Copped Hall registered park and garden would occur in this area due to intervening distance and established vegetation within and outside the highway boundary. No Changes to Upshire Conservation Area, or its setting, are anticipated due to the location of the Project within the existing highway boundary and the prescence of established vegetation within the highway boundary here. No impact on Oxleys Wood ancient woodland would occur, as it is located a minimum of 50 metres to the north of the M25. A very minor loss of existing vegetation, within the soft estate would occur. Magnitude of Impact: Negligible Adverse. D1: Epping Forest and Ridges 7.7.10 This area crosses the M25 at Epping Forest and Bell Common Tunnel. There would be no impact on Griffins Wood ancient woodland due to intervening distance from the Project. The Conservation Area at Bell Common would not be affected by the Project, due to the existing tunnel and intervening vegetation. The Project would have no impact on Coopersale House Registered Park and Garden and Coopersale Street Conservation Area due to the distance between them and the Project. 7.7.11 The Project would result in a very minor change to key landscape elements at Copped Hall historic park and garden and Copped Hall Conservation Area where they cross the M25 corridor. These changes would be seen in the context of the existing motorway corridor. The gantries at
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chainage 58,740 and 59,505 are located in cuttings with woodland on either side so are well screened. The gantry at chainage 59,880 is in open ground but would be partially screened from nearby receptors by existing off site vegetation and new planting where space permits. New gantries (replacing unsuitable existing ones) and signs to the east of the Bell Common Tunnel would be well screened by cutting and vegetation within the highway boundary. Magnitude of Impact: Negligible Adverse. C4: Roding Valley 7.7.12 This area crosses the M25 at Junction 27 where the Project includes two new and two replacement gantries. The Project would have no direct or indirect impacts on Barber‟s Wood ancient woodland due to intervening distance. The Project would have no direct or indirect impact on Hill Hall registered park and garden or Hill Hall Conservation Area due to intervening distance and the extent of existing views to Junction 27. A very minor loss of existing vegetation, within the soft estate would occur. Magnitude of Impact: Negligible Adverse. L1: Potters Bar 7.7.13 This area lies to the north of the M25 between Junction 23 and Junction 24. The Project would not directly impact on this area, there would be no direct impact on the Royds Conservation Area, Potter Bar. No impacts on the setting of the Conservation Area are anticipated from the Project due to intervening distance and vegetation. No loss or alteration of landscape elements / attributes is anticipated. Magnitude of Impact: No Change. L2: Holly Hill Farmland 7.7.14 This area lies immediately to the south of the M25 to the east of Junction 24. New gantries and ERAs, including lit matrix signs, are proposed in this area. No impact on the area of special character located within this area is anticipated from the Project, all work proposed is located within the highway boundary. There would be a very minor loss of mature vegetation within the soft estate. Magnitude of Impact: Negligible Adverse. L3: Whitewebbs Parkland 7.7.15 This area lies to the south of the M25, at Whitewebbs. No impacts on the registered historic park and garden of Myddelton House would occur due to intervening distance and screening by vegetation. There is potential for a very minor change to the setting of Forty Hall Conservation Area due to its direct proximity to the Project, however these changes would be seen in the context of the existing M25 corridor. There would be no observable adverse or beneficial impacts resulting from the Project on this area. Magnitude of Impact: No Change. L4: Waltham Cross and North Enfield 7.7.16 This largely industrial area crosses the M25 at Waltham Cross and includes Holmsdale Tunnel. Widening to four lane adjacent to Holmsdale Tunnel, gantries and cantilever signs including lit matrix signs are proposed, , in this area. Very minor changes to the Lee Valley Regional Park character and area of special character are anticipated, due to direct proximity to the project, however these changes would be seen in the context of the existing M25 corridor which is industrialised. There would be a minor loss of vegetation within the soft estate. Magnitude of Impact: Negligible Adverse. Visual Impacts 7.7.17 The visual magnitude of impact for all visual receptors within the Study Area has been assessed for Year 1 and Year 15 based on the criteria set out in the methodology section (refer to Section 7.3, Table 7.8) and is included in full in the Visual Impact Schedule (refer to Appendix F).
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7.8 Significant Effects Landscape Significance of Effect 7.8.1 The significance of landscape effects, based on landscape sensitivity and landscape magnitude (in accordance with the methodology in Section 7.3), is provided below for each of the character areas. Table 7.10 - Summary of Landscape Effects Landscape Character Area Landscape Landscape Significance of Sensitivity Magnitude Effect – Year 1 (and (Year 1) Year 15 if different) 21: High Canons Valleys and Moderate No Change Neutral Ridges 24: Arkley Plain Low Negligible Adverse Neutral 25: Wrotham Park and Moderate Negligible Adverse Slight Adverse Bentley Heath 26: Hornbeam Hills (Enfield Low Negligible Adverse Neutral Chase) 27: Catherine Bourne Valley Moderate No Change Neutral 53: Northaw Common Low Negligible Adverse Neutral Parkland 55: Theobalds Estate Low Negligible Adverse Neutral C3: Lee Valley Moderate Negligible Adverse Slight Adverse D1: Epping Forest and High Negligible Adverse Slight Adverse Ridges C4: Roding Valley Moderate Negligible Adverse Slight Adverse L1: Potters Bar Moderate No Change Neutral L2: Holly Hill Farmland Moderate Negligible Adverse Slight Adverse L3: Whitewebbs Parkland Moderate No Change Neutral L4: Waltham Cross and North Low Negligible Adverse Neutral Enfield
7.8.2 Overall an increase in gantries and signage will slightly increase the perception of urbanisation in the countryside and result in a very minor loss to landscape features within the highway boundary. Overall the landscape effect of the Project would be Slight Adverse. Visual Significance of Effect 7.8.3 The visual significance of effect, for all visual receptors within the Study Area has been assessed for Year 1 Summer and Year 15 Summer and Winter based on the criteria set out in the methodology section (refer to Section 7.3) and is included in full in the Visual Impact Schedule (refer to Appendix F). The visual significance of effect is also shown diagrammatically on Figures 7.3 and 7.4 for Year 1 Summer and Year 15 Summer respectively. The following tables provide a summary of the visual effects for the Project.
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Table 7.11 - Summary of Visual Effects Year 1 (Winter) Receptor Type No. of Receptors Slight Neutral Slight Moderate Large Beneficial Adverse Adverse Adverse Properties - 27 45 11 - Footpaths 1 23 25 - - Open Space - 9 11 - - Roads - 23 8 - - Totals 1 82 89 11 -
Table 7.12 - Summary of Visual Effects Year 15 (Summer) Receptor Type No. of Receptors Slight Neutral Slight Moderate Large Beneficial Adverse Adverse Adverse Properties - 37 39 7 - Footpaths 1 24 22 - - Open Space - 13 7 - - Roads - 24 7 - - Totals 1 99 75 7 -
7.8.4 One receptor – the cycleway and footpath along Wash Lane and Mimmshall Brook near South Mimms Services – is identified as having a Slight Beneficial visual effect due to an existing highly visible gantry being removed from the scene, thereby improving the aspect from the southern approach towards the M25. 7.8.5 11 receptors are identified as having Moderate Adverse visual effects at Year 1, all of which are properties. At 6 of these sites it is recommended that on-site mitigation planting is implemented to reduce the long term visual effects. These properties would have either direct close-range views to proposed gantries or longer range views over intervening open land towards the Project. At Year 15 the total reduces to 7, as intervening vegetation matures to filter the view and visual effects are reduced. 7.8.6 No receptors are identified as having Large Adverse visual effects at Year 1 or Year 15. 7.8.7 The majority of the effects of the Project are Neutral or Slight Adverse due to the location of all proposed work within the existing M25 highway boundary which with existing lighting and signage has an adverse visual effect. Overall the Project would have a Slight Adverse effect on visual amenity, predominantly due to a minor increase in visual intrusion resulting from proposed gantries. Overall the visual effect of the Project would be Slight Adverse. Significance of Effects on Plans and Policies 7.8.8 Of the national, regional and local policies outlined in Section 7.5, the predicted level of impact on landscape and visual amenity has the potential to hinder some of the policies. The following policies would experience a Slight Adverse effect:
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National - none Regional - ENV1, ENV5, (East of England Plan) 2.18, 7.21 (London Plan) Local - R17 (Welwyn Hatfield District Plan) HC5, (Epping Forest District Plan) CLT4 (Borough of Broxbourne Local Plan) 7.8.9 The following policies would experience a Neutral effect: National - NPPF, Core Principle 11. Regional - Local - NC4, HC3, HC6, RST24 (Epping Forest District Plan) 31, 34, 35 (London Borough of Enfield Core Strategy) C7, C9, E27 (Hertsmere Local Plan) 7.9 Indication of Any Difficulties Encountered 7.9.1 No difficulties were encountered in the assessment. 7.10 Summary 7.10.1 This Chapter has assessed the landscape and visual effects of the Project at Year 1 and Year 15. 7.10.2 No effects on landscape have been assessed as any worse than Slight Adverse. 7.10.3 No Large Adverse visual effects have been identified.. 7.10.4 Moderate Adverse visual effects have been identified at 11 receptors, all of which are properties, at Year 1, reducing to 7 overall in Year 15. With on-site mitigation planting the effects can be reduced to Slight Adverse in Year 15 at 6 receptor sites. The remainder of sites offer limited or no opportunity for mitigation due to either insufficient available on-site space for planting and / or the prominent position of a gantry which cannot be effectively mitigated against. In some such situations it is recommended that either the gantry position be further reviewed or that off-site planting is considered. 7.10.5 The effects of the Project on landscape character and visual amenity on the majority of resource / receptors in the study area are generally Neutral or Slight Adverse due to the location of all proposed work within the existing M25 highway boundary and the restricted nature of the works. The Project would, however, result in a minor increase in visual intrusion and a slight increased perception of urbanisation in the countryside resulting from the proposed gantries. Overall the Project would have a Slight Adverse effect on landscape and visual amenity.
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8. Nature Conservation 8.1 Study Area 8.1.1 The study area for this assessment has been defined by determining a zone of influence encompassing all predicted adverse ecological effects of the scheme, including those which occur by land-take and habitat loss and those which occur through disturbance, such as noise. 8.1.2 The following search areas either side of the centre line of the scheme have been used when gathering information for the desk study: 30km for Special Areas of Conservation (SACs) where bats are one of the qualifying species; 2km for Natura 2000 sites (all other Special Areas of Conservation (SACs), Special Protection Areas (SPAs)); Ramsar sites; and nationally important statutory sites of nature conservation importance, such as Sites of Special Scientific Interest (SSSIs); 500m for non-statutory sites of nature conservation importance, protected or notable species (except for bats) and ponds that could offer the potential to support great crested newts (GCNs); and 10km for records of bats. 8.1.3 For field survey the area within the Highways Agency boundary plus 150m either side of the centre line of the scheme was surveyed during the Phase 1 habitat survey. Search zones used for additional surveys are detailed within each of the individual reports, provided as Appendices, as detailed in Table 8.1. Table 8.1 - Ecology Appendices and Document References
Survey Report Title Appendix Document reference
M25 Later Upgraded Section 5 Junctions Appendix D1 5084755-S5-DO-EN-147 23 to 27 Desk Study 2010
M25 Later Upgraded Section 5 Junctions Appendix D2 5084755-S5-DO-EN-146 23 to 27 Phase 1 Habitat survey 2010
M25 Later Upgraded Section 5 Junctions Appendix D3 5084755-S5-DO-EN-145 23 to 27 Bat survey 2009 -2010
M25 Later Upgraded Section 5 Junctions Appendix D4 5084755-S5-DO-EN-143 23 to 27 Dormouse survey 2010
M25 Later Upgraded Section 5 Junctions Appendix D5 5084755-S5-DO-EN-142 23 to 27 Otter and water vole survey 2010
M25 Later Upgraded Section 5 Junctions Appendix D6 5084755-S5-DO-EN-144 23 to 27 Reptile survey 2010
M25 Later Upgraded Section 5 Junctions Appendix D7 N/A 23 to 27 Great Crested Newt Survey 2010
8.2 Methodology Establishment of Baseline Conditions 8.2.1 As described in section 8.3, establishment of baseline conditions involved the review of existing published data, update of the desk study, verification and revision of the Phase 1 Habitat Survey with additional field surveys carried out where the Phase 1 survey and previous data indicated that
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there was a potential for significant ecological impacts as a result of the scheme, in particular where there was the potential for rare or protected species or habitats to be impacted. Full methodologies and results for each of the surveys carried out are provided in Appendices D2 to D7. A summary of relevant legislation is provided in Appendix D1 Determining the Significance of Effects 8.2.2 The level and scope of assessment carried out is a detailed assessment in accordance with DMRB Volume 10, Section 2, Part 4. Impact assessment and determination of significance of effects follows Interim advice Note (IAN) 130/10 Ecology and Nature Conservation: Criteria for Impact Assessment (Highways Agency, 2010). IAN 130/10 provides an approach for relating significant impacts on receptors at different levels of nature conservation value to overall significance of effect categories. Significance of effect categories, as defined in IAN130/10, are shown in Table 8.2. Table 8.2 - Significance of Effects Categories as Defined in IAN 130/10 Significance Typical Description of Effect (Nature Conservation) Category Very Large An impact on one or more receptor(s) of International, European, UK or National Value. NOTE: only adverse effects are normally assigned this level of significance. They should be considered to represent key factors in the decision-making process. Large An impact on one or more receptor(s) of Regional Value. NOTE: these effects are considered to be very important considerations and are likely to be material in the decision-making process.) Moderate An impact on one or more receptor(s) of County or Unitary Authority Area Value. NOTE: these effects may be important, but are not likely to be key decision-making factors. Slight An impact on one or more receptor(s) of Local Value. NOTE: these effects are unlikely to be critical in the decision-making process, but are important in enhancing the subsequent design of the project. Neutral No significant impacts on key nature conservation receptors. NOTE: absence of effects, or those that are beneath levels of perception.
8.2.3 As required in the Highways Agency‟s guidance on this topic, Interim Advice Note (IAN) 130/10, Section 2.5, professional judgement has been applied and in this assessment the value of the resource, characterisation of the impact and the scheme specific circumstances are considered in arriving at significance of effect categories. Professional judgement is required as there is no single common methodology for this process. 8.3 Baseline Conditions 8.3.1 A number of previous studies have been used to inform the baseline conditions. The M25 Widening Section 5 (Junctions 23 to 27) Environment Assessment Report (EAR) (Highways Agency, 2007) and Addendum Report (Highways Agency, 2007) presented baseline conditions established from existing published data and field survey data. Field survey data included a Phase 1 Habitat Survey conducted in summer 2004 with updates in 2006 and initial surveys for protected species conducted in 2005 and 2006. An update of the desk study was carried out in 2008 and a walkover survey to update the information collected in 2004 and 2006 was carried out during 2009 and reported in the Draft Stage 2 EAR. 8.3.2 For the detailed assessment, the desk study has been updated with data obtained during 2010/2011 (see Appendix D1). A verification of the Phase 1 survey has been undertaken with additional field surveys carried out where the Phase 1 survey and previous data indicated that there was a potential for significant ecological impacts as a result of the scheme, in particular
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where there was the potential for rare or protected species or habitats to be affected. Full methodologies and results for each of the surveys carried out are provided in Appendices D2 to D7. A summary of relevant legislation is provided in Appendix D1. Designated Sites 8.3.3 There are five statutory designated sites located within the two kilometres search area. These are: Epping Forest SSSI (also designated as Epping Forest SAC); Turnford and Cheshunt Pits SSSI (also designated as part of the Lee Valley Ramsar Site and SPA); Cornmill Stream and Old River Lea SSSI; Waltham Abbey SSSI; and Chingford Reservoirs SSSI. A summary of their features of interest is provided in Table 8.3 and full details of their locations and citations are provided in Appendix D1. Sites also listed on the provisional Ancient Woodland Inventory are shown in bold in Table 8.4. 8.3.4 No SACs designated for their bat interest were identified within 30km of the project. 8.3.5 As part of the process of assessment of ecological impacts, a separate document has been prepared entitled “Assessment of Impacts on European Sites” (AIES) which assesses potential impacts of the scheme on NATURA 2000 sites. This has been undertaken for both Epping Forest SAC and Lee Valley SPA. Table 8.3 - Statutory Designated Sites with 2km of the Scheme
Name of Designation Summary site/Designation
Epping Forest SAC and Adjacent to scheme. One of a few remaining large-scale examples of SSSI* ancient wood-pasture in lowland Britain. Includes ancient semi-natural woodland, old grassland plains and scattered wetland. Supports a range of rare and otherwise important species of flora and fauna, including a nationally outstanding assemblage of invertebrates (including the stag beetle), a major amphibian interest and an exceptional breeding bird community.
Cornmills Stream and Old 900m upstream. A freshwater habitat with one of the most diverse River Lea SSSI invertebrate faunas in Essex including a number of scarce species. This SSSI is directly connected to the River Lee Navigation, which flows beneath the M25 downstream of the SSSI.
Lee Valley SPA and 1,100m upstream. Series of embanked water supply reservoirs, RAMSAR Site, which sewage treatment lagoons and former gravel pits. The site is of note for includes Turnford and its ornithological interest, which is of European importance. This SPA is Cheshunt Pits SSSI directly connected to the River Lee Navigation, which flows beneath the M25 downstream of the SPA.
Waltham Abbey SSSI 1,330m from scheme. Ancient alder woodland within the River Lee valley. The site supports the largest heronry in Essex.
Chingford Reservoirs 1,960m downstream. One of the major wintering grounds for wildfowl SSSI and wetland birds in the London area. It holds nationally important numbers of some species. The SSSI is directly connected to the River Lee Navigation, which flows beneath the M25 upstream of the SSSI. *Site is on the provisional Ancient Woodland Inventory 8.3.6 There are 24 non-statutory designated sites located within 500 metres of the centre line of the M25 Junctions 23 to 27. Table 8.4 lists these from west to east and includes summaries of the features for which they were selected for designation. Sites also listed on the provisional Ancient Woodland Inventory or containing ancient woodland, but not shown on the inventory, are shown in bold in Table 8.4. 8.3.7 Full details of their locations and citations are provided in Appendix D1. The terminology used for non-statutory sites varies between counties. The counties through which the scheme runs use the following terms to designate their areas of local nature conservation importance:
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Hertfordshire - County Wildlife Site (CWS); Essex - Local Wildlife Site (LoWS); and London – Sites of Importance for Nature Conservation (SINCs), which are further subdivided. The sub-divisions relevant to the search area are: Site of Borough (Grade 1) Importance for Nature Conservation (SBINCs) and Site of Metropolitan Importance for Nature Conservation (SMINCs).
Table 8.4 - Non-statutory Designated Sites within 500m of the Scheme Name of Designation Summary site/designation Wash Lane CWS Linear area of common land alongside the Mimmshall Brook, supporting grassland, marshland, two dry ponds and swamp. There is a good plant diversity here including several species that are uncommon in the Hertfordshire area. Additionally, the site is known to support grass snakes. Wash Lane Old Common with large hedgerows, rough wet grassland, neutral grassland Common and (with indicator species), tall herb vegetation and scrub. This site has habitats Dancers Hill with good botanical diversity. Common CWS Elm Farm pasture Semi-improved grassland with damp areas and a pond that is important for area CWS amphibians. Pond by Bentley Designated for its population of great crested newts. Heath Church CWS Bentley Heath Spring-fed pond designated for its population of great crested newts. pond CWS Ganwick Corner Designated for its population of great crested newts. pond CWS Fenny Slade Hill Unimproved / semi-improved rough grassland with neutral indicator species. CWS Some wet grassland around a pond. Five Acre wood A small section of this site is just within the 500m boundary. CWS Semi-natural oak/hornbeam woodland developed from ancient wood pasture which was formerly part of the Enfield Chase. Fir and Pond This is described as the best remaining part of the Enfield Chase. It contains a Wood Nature mixed area of woodland, plantation and acid grassland bordered by the Turkey Reserve CWS* Brook. The area is important for great crested newts and its dragonfly species assemblage. Cattlegate Wood Mature hornbeam coppice with oak standards. Contains 24 ancient woodland CWS* indicator plants and two small ponds. Crews Hill Golf A small section of this site is within the 500m boundary. It contains some of Course SBINC the best relic acid grassland in the borough of Enfield. Cattlin‟s Wood Old semi-natural woodland of hornbeam and hazel coppice with oak standards. CWS Contains a small stream and some ancient woodland indicator plants. The New River This site is considered one of London‟s cleanest waterways, supplying drinking SMINC water from chalk springs in Hertfordshire. It contains rare plants (including the nationally declining river water dropwort (Oenanthe fluviatilis) and a good range of aquatic invertebrates (indicated by range of dragon/damselflies) and fish. Kingfisher are also thought to breed on this watercourse. Lower Lea Valley This site includes the River Lee Navigation, River Lea and associated SMINC downstream watercourses, Ramney Marsh, King George V and William Girling Reservoirs, Walthamstow Marshes and Reservoirs and the new Middlesex Filter Beds nature reserve. The site supports diverse aquatic flora including the nationally rare and specially protected creeping marshwort (Apium repens) in a ditch beside Walthamstow Marshes. The neutral grassland contains a
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Name of Designation Summary site/designation similarly diverse flora including the nationally Scarce yellow vetchling (Lathyrus aphaca). The site supports internationally important numbers of wintering gadwall and shoveler, along with other nationally important birds and the reed beds support a nationally important assemblage of invertebrates. In addition to this there are records of water vole, great crested newt and declining bullhead along with several nationally scarce moths. Gunpowder Park The northern end of this designated brownfield site is just within the 500m LoWS boundary. Rough grassland with 11 nationally rare Red Data Book invertebrates and 66 species of Essex Red Data List species. Also supports a locally important population of breeding skylark. Conybury Wood The northern part of this site is ancient woodland, while the southern half is LoWS* recent secondary growth. Contains mature beech, oak and hornbeam, plus rhododendron. Ground flora is sparse. Oxleys Wood A network of woodland and interconnecting green lanes, once contiguous with Complex LoWS* Epping Forest and bearing many similar characteristics. Directly adjacent to the motorway are Potkiln wood (non-ancient woodland with limited ground flora) and Green Lane. Set further back, but still within 500m are Oxleys Wood (area of ancient oak woodland with coppiced hornbeam and hazel but limited understory and ground flora, included on the Provisional Ancient Woodland Register), Blind Lane, Sergeants Lane and Rugged Lane. Green Lane and Originally connected to Oxleys Wood Complex (above) but was cut off by the Brambly Shaw M25. Still an important dispersal route from Epping forest especially for LoWS** invertebrates. The composition of the ground flora suggests that Brambly Shaw is possibly part ancient woodland. Copped Hall Green A large mosaic of oak/ash woodland, plantation, neutral grassland and ponds LoWS that forms a natural link to other LoWS including: Epping Forest, Oxley‟s Wood Complex and Rookery Wood. The Selvage LoWS Linear woodland dominated by pedunculate oak with some sycamore and hornbeam. Ground flora is sparse with locally dominant patches of bluebell and dog‟s mercury and some hazel coppice stools. Griffin’s Wood Hornbeam coppice with oak and occasional ash standards ancient woodland. LoWS* Has limited ground flora in localised patches and a small pond in the northern corner. Bell Common and This site is a mosaic of established acid grassland, secondary broadleaved Ivy Chimneys woodland, scrub and freshwater located at the Bell Common tunnel. Of Complex LoWS particular note are the acidic grassland and aquatic fauna and flora. Blunts Farm Hornbeam woodland with stands of pedunculate oak and ash. Several ancient Wood LoWS** woodland indicators in ground flora assemblage. Blunts Farm Sparsely vegetated, hummocky ground containing open mosaic habitats which Brownfield LoWS support a diverse assemblage of invertebrates. There is also valuable dead wood present and a large pedunculate oak known to support a population of the Nationally Scarce ant (Lasius bruneus). *Site is on the provisional Ancient Woodland Inventory **Site contains ancient woodland but is not on the ancient woodland inventory
Habitats 8.3.8 Survey methods, results of the Phase 1 Habitat Survey and the Phase 1 habitat survey map can be found in Appendix D2. The survey identified a range of habitats within the study area, including those present on the motorway verge including:
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Woodland (semi-natural broadleaved, mixed broad-leaved plantation); Scattered trees; Hedgerows and hedgerow trees; Scrub – dense and scattered; Grassland (semi-improved neutral, improved and amenity grassland); Aquatic habitats (dry ditches, standing and running water); and Other habitats - tall ruderal, ephemeral, bare ground, introduced shrubs. 8.3.9 Additionally, in adjacent habitats up to 150m from the Highways Agency boundary: Mixed semi-natural woodland; Arable; and Urban areas. 8.3.10 Most of the vegetation on the verges consists of species-poor common and widespread vegetation. Some of the above habitats are UK, Hertfordshire, Essex or London Biodiversity Action Plan (BAP) priority habitats. Priority habitats consist of 38 key habitats, which the UK is internationally committed to protect due to decline or rarity. In addition, some are habitats of principal importance for the conservation of biodiversity in England (under Section 41 of the Natural Environment and Rural Communities Act (NERC) 2006) as detailed further in Appendix D2. 8.3.11 Boundary Features (including hedgerows, walls and ditches), grassland features, water features (including ditches, balancing ponds or lagoons, rivers, streams and canals), and woodland features are included in the Highways Agency BAP (HABAP). Non Native Invasive Species 8.3.12 The list of invasive plant species included on Schedule 9 of the Wildlife and Countryside Act 1981 (as amended) is extensive and these plants are found in a range of different habitats, including aquatic habitats. The extended Phase 1 survey has checked, in particular, for the presence of Japanese knotweed, giant knotweed, hybrid knotweed, giant hogweed, rhododendron and Himalayan balsam. There may be other invasive plant species present within the scheme area which were not recorded, but it is considered that this survey is sufficient to identify any significant constraints posed by invasive plants. The following species have been identified within the highway boundary: Japanese knotweed; Himalayan balsam; Rhododendron; and Parrots feather. 8.3.13 The locations where these were found are provided in Figure 3.1 to 3.17 in Appendix D2. It is an offence to plant these species or otherwise cause them to grow in the wild. 8.3.14 Although not currently included within Schedule 9 of the Wildlife and Countryside Act (as amended) Natural England, in their response to the EAR Scoping Report, has noted that “goat‟s rue and Michaelmas daisy have both shown significant increases in the London Basin area over recent years and are becoming quite troublesome and invasive weeds.” Goat‟s rue is listed on the London Invasive Species Initiative list of species of concern under category 4 (Species which are widespread for which eradication is not feasible but where avoiding spread to other sites may be required). Both of these species are present on Section 5, with locations of these species provided in Figure 3.1 to 3.17 in Appendix D2.
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Protected or Otherwise Notable Species 8.3.15 A summary of relevant legislation can be found in Appendix D1. Full details of desk study data, survey methods and results for protected and notable species can be found in Appendices D2 to D7. Figures 3.5 to 3.8 provide a map to show records of protected species, except for bats, which are shown in Figure 3.9. A summary of key findings is provided below. 8.3.16 For those species where specialist detailed protected species surveys were not considered necessary further information is provided in Appendix D2 along with the Phase 1 habitat survey results. Notable Plants 8.3.17 The Nationally Scarce Yellow Vetchling (Lathyrus aphaca) was recorded during the walkover survey on the verge adjacent to Gardners Underbridge to the west of Junction 27, on the anticlockwise side. This species is relatively widespread in the south east of England and the population present on the verge is limited to a small area. Mammals Badger 8.3.18 Although badgers are not listed under the UK or local Biodiversity Action Plans, they are included in the HA BAP as being particularly susceptible to road impacts. 8.3.19 The networks of habitats present within the study area (including woodland, scrub, hedgerows and grassland) provide high quality habitat for badgers. 8.3.20 Evidence of badgers was noted in localised areas along the length of the project area, with two active „main‟ setts located within the Study Area between Junctions 24 and 25, one within 30m of the scheme and another within 150m. Various other signs of badger were recorded such as latrines, badger hair and paths within a variety of habitat types including woodland, grassland, arable land, tall ruderal herbs and scrub. Appendix D2 provides further details and locations of setts and other signs recorded. Exact locations of badger setts should be kept strictly confidential due to issues associated with badger baiting and can only released to qualified persons upon request. Bats 8.3.21 Full details of desk study and field survey data for bats can be found in Appendix D3. 8.3.22 Hertfordshire Biological Records Centre (HBRC) identified eight areas that seem to be of particular use to bats. Some are more than 2km from the motorway but with good connectivity, meaning that verges could still be used for foraging. The bat species recorded within 10km of this section of road are; Brandt‟s, brown long-eared, Daubenton‟s, Leisler‟s, Natterer‟s, noctule and pipistrelle species. In addition there are four known brown long-eared bat roosts within 10km of the scheme: one at Ramney Marsh; one at Waltham Abbey; and two within Epping comprising one on B1393 High Road and the other on Stewards Green Road. 8.3.23 Greenspace Information for Greater London (GiGL) information showed that six species of bat have been recorded in the search area. The most frequently recorded are the pipistrelle species, which have a number of records throughout the desk study area. Records for three areas along the section between Junction 24 to 25 show a range of bat species to be present. These include a number of records of pipistrelle species, Daubenton‟s, Natterer‟s and brown long-eared bats around Junction 24 in the Potters Bar area. The areas northwest and southwest of Junction 25 have records of pipistrelle, Daubenton‟s, Natterer‟s, brown long-eared and noctule. 8.3.24 Essex Ecology Services Ltd (EECOS) reported one pipistrelle bat in Gernon Bushes Wildlife Trust Reserves.
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8.3.25 Information received from City of London ecologists showed that eight species of bats have been recorded in the Warren Plantation, adjacent to Epping Forest SAC including common, soprano and Nathusius‟ pipistrelle, noctule, Leisler‟s, Natterer‟s, brown long-eared and barbastelles. 8.3.26 Barbastelle, Noctule, brown long-eared and soprano pipistrelle bats are UK BAP Priority species, all bats in London are included in the London BAP and common pipistrelle and Nathusius‟ pipistrelle are Essex BAP species, while Natterer‟s and common pipistrelle are both on the Hertfordshire BAP. All bats are included in the HABAP. 8.3.27 The habitats located between J23 and J27 on the M25 consist of a variety of features which could support commuting and foraging bats. These features include scrub along the verges of the M25 and a mixture of arable fields, pasture, hedgerows, woodland edges and watercourses in some of the adjacent land. 8.3.28 A total of 51 potential bat roosting sites were identified within the study area during the initial surveys in 2005. Sixteen of the features were considered to be of moderate potential to support roosting bats, many of which also had the potential to act as commuting corridors over or beneath the motorway. A total of six trees with bat roost potential were identified within the Study Area. 8.3.29 In 2009 / 2010 bat surveys were conducted at bridges and on areas of suitable habitat that were thought likely to be affected by the proposed scheme and which had high-moderate potential to support bat roost as identified by the bridge assessments. Dusk and dawn surveys and transect surveys were undertaken to record bat activity and to detect evidence of any bat roosts or crossing points. 8.3.30 None of the bridges surveyed were confirmed as supporting bat roosts in 2009 or 2010. Some bridges surveyed in 2009 indicated that they were used by bats as crossing points, most notably Wash Lane Underbridge, New Cottage Farm Underbridge and River Lee Underbridge. 8.3.31 Other bridges and habitats within the transects surveyed can also be considered as important crossing points, foraging areas and commuting corridors as evidenced by the high activity levels observed during some of the surveys, as shown in Appendix D3 Figure 2.1 to 2.4. 8.3.32 Bat species recorded during the field surveys included: common, soprano and Nathusius‟ pipistrelle, serotine, noctule, Myotis species and a possible Leisler‟s bat. Long-eared bats have a quiet call and therefore are difficult to detect during transect surveys and are likely to have been under-recorded, but the number of records of long-eared bats and roosts provided by HBRC confirm that they are common within some of the survey area. Dormouse 8.3.33 Full details of desk study and field survey data for dormice can be found in Appendix D4. The dormouse is a UK BAP, Hertfordshire, Essex and London BAP Priority species and is included in the HABAP. 8.3.34 No dormouse records were available for the survey area from HRBC or GiGL. EECOS held two negative records (i.e. records where surveys were undertaken and no dormice were found) for dormice in the Essex area dating from 2003 with one record being from Upshire, Epping and the other one from Connaught Water. 8.3.35 Surveys were carried out in October / November 2005, which included nut searches and the use of nesting boxes and tubes within the most suitable habitat types, woodland and hedgerows, within and adjacent to the project area. A further nest tube survey was undertaken from May to October 2010. No signs of dormouse activity were recorded during these surveys. 8.3.36 Natural England, in their response to the EAR Scoping Report, has noted that “recent experiences in South Essex and on the Essex-Herts borders suggest that dormice can exist within a wider range of habitat than was previously considered to be the case and may be present at extremely low population density within such habitats as scattered hawthorn scrub or patches of bramble, even within areas for which there are no recent records. As their presence under these conditions
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is very difficult to detect by the standard survey techniques, we recommend that, irrespective of survey results, appropriate mitigation measures (such as ensuring ecological supervision of all tree/scrub/hedge removal) should be put in place”. Therefore, it is theoretically possible that dormice may be present, but remain undetected by surveys, in woodland and scrub habitats within the HA boundary, particularly where they link to woodland. Otter 8.3.37 The otter is a UK BAP Priority species and is also listed on the Essex, London, Hertfordshire and HA BAPs. 8.3.38 There are desk study records from 2000 onwards of otter from the three Biological Record Centres and Essex otter survey (Tansley, 2009). These include records of otters on the Small River Lee, north of the M25 (2009), otter spraints near the Small River Lea bridge (2004), on the Small River Lee, south of the M25 (2004), the Old River Lee, north of the M25 (2004) and continual positive otter signs on the River Lee/Lea (found between 2003 and 2008). All the records have been compiled into a species distribution map, which can be found in the Appendix D2. 8.3.39 All watercourses within 500m of the scheme boundary were surveyed during 2005/2006 and evidence of others was found on for a number of watercourses between Junctions 25 and 27. Specifically, signs of otters were recorded at bridges which are located within the Lee Valley and the River Roding catchment along the tributary watercourses in the vicinity of Junction 27; although no holts or lying up sites were recorded. 8.3.40 In July 2010 otter surveys were carried out on nineteen watercourses which were thought likely to be affected by potential changes to slip roads at junctions, those within 500m of each Junction. Only two watercourse sites were found to have any signs suggesting potential presence of otter during the 2010 surveys, one of which was Hobbs Cross stream, where signs had been found in 2005. Full details of the methods and results of the survey undertaken in 2010 can be found in Appendix D5. Water Vole 8.3.41 The water vole is a UK BAP Priority species and are also listed on the Essex, London, Hertfordshire and HA BAPs. 8.3.42 Records obtained during the desk study for the 2007 EAR showed that water voles inhabited ponds within Fir and Pond Wood Nature Reserve and watercourses within the Lee Valley complex. Water voles are known to be present throughout the catchment of the Lee. 8.3.43 Water vole surveys were conducted on all watercourses within 250m of the scheme boundary in 2006. The presence of water voles was confirmed at Mimshall Brook and two ponds adjacent to Mimshall Brook near Junction 23 (where burrows and feeding signs were recorded). During the walkover survey the stone gabions of Cobbin‟s Brook and Turkey Brook were noted as being suitable water vole habitat. 8.3.44 In July 2010 water vole surveys were carried out on nineteen watercourses which were thought likely to be affected by potential changes to slip roads at junctions, because they were within 500m of each junction. No confirmed signs of water voles were found on any of the watercourses surveyed in 2010. Full details of the methods, results and maps of the survey undertaken in 2010 can be found in Appendix D5. Deer 8.3.45 The legal protection relating to deer deals with cruelty and also the methods and seasons during which the four main species can be killed. Deer are considered because deer crossing roads can result in road traffic accidents and hence there are road safety and animal welfare issues that may need to be considered.
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8.3.46 Species of deer including fallow, Chinese muntjac, and roe have been recorded along the length of Section 5, particularly in the vicinity of wooded and rough grassland areas such as Epping Forest, Barber‟s Wood, and Fir and Pond Wood Nature Reserve, including sightings of a herd of at least 50 fallow deer on the clockwise side of the M25 opposite The Warren between Junctions 26 and 27 (EAR, 2007). Further details are provided in Appendix D2. Herptiles Amphibians 8.3.47 Great crested newts (GCN) are a UK BAP Priority species and are also listed on the Hertfordshire, Essex, London and HA BAP. Common toads are also included in the HABAP. 8.3.48 Desk study records of GCN exist for sites within Bentley Heath Pond, Fir and Pond Wood Nature Reserve, Epping Forest, and Epping town, Oxleys Wood Complex, Ivy Chimneys Complex, Whitewebbs Park to the south of the Project west of Junction 25, in the vicinity of Junction 27 within the adjacent golf courses. 8.3.49 The amphibian assemblages of Epping Forest SSSI and Turnford and Cheshunt Pits SSSI are listed within their citations. Additionally, great crested newts are listed in five non-statutory site designations. Three of these five are ponds are designated for their GCN populations: Pond by Bentley Heath Church; Bentley Heath pond and Ganwick pond; all within 500m of the scheme. 8.3.50 GCN surveys undertaken in 2010 consisted of identification of ponds within 500m of the scheme, habitat assessment of those ponds for their suitability for GCN, and then detailed surveys for presence / absence and to provide population estimates were found to be present or where considered appropriate. Full details of the surveys can be found in Appendix D7. 8.3.51 The habitats present on the motorway verge and throughout the study area provide suitable terrestrial habitat for great crested newts with good habitat connectivity provided by linking hedgerows and woodlands. 8.3.52 During the 2010 survyes, of the 109 water bodies identified; Great crested newts were found to be present within twenty ponds; The likely absence of great crested newts was confirmed (in 2010) within thirty seven ponds and one ditch over the course of four presence/likely absence pond surveys; A total of sixteen water bodies were not found to be present during the surveys; Seventeen waterbodies could not be surveyed due to the landowners refusing access; Landowners could not be identified for six water bodies; Landowners could not be contacted for four waterbodies. Access could not be gained to two ponds due to health and safety / physical barriers. Sixteen ponds were not surveyed due to the M11 providing a barrier between the water bodies and Section 5. 8.3.53 Ponds within 50m of the scheme were re-surveyed in 2012. In addition, where access could not be obtained in 2010, but was subsequently granted in 2012, surveys were carried out of four additional ponds, but none of these additional ponds confirmed presence of great crested newts. 8.3.54 Full survey methods and results including detailed maps can be found in Appendix D6. Reptiles 8.3.55 Slow worm, grass snake, common lizard and adder are all identified as priority species on the UK and London BAP. All native species of reptile are included in the HABAP. 8.3.56 Records of slow-worm, grass snake, common lizard and adder exist for locations throughout the study area, but particularly within the area of Epping Forest.
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8.3.57 Reptiles are likely to be present within rough grassland, scrub and woodland habitat, including along the embankments and cuttings of the M25. Two grass snakes were observed incidentally adjacent to Cobbin‟s Brook during the walkover survey in 2006, and a bank between the railway line and Junction 27 was noted as being suitable for hibernating reptiles. 8.3.58 A presence / absence reptile survey was undertaken in May / June 2010 using artificial refugia within twenty-five sample areas representative of suitable habitat within the scheme study area. In summary, the survey identified reptiles as being present in five of the twenty-five survey areas along the scheme. Reptile species recorded were grass snake and common lizard. 8.3.59 Full survey methods and results including detailed maps can be found in Appendix D6. Birds 8.3.60 Habitats including woodland, scrub, hedgerows, trees, rough grassland and built structures, such as over bridges, throughout the project area are suitable for breeding birds. 8.3.61 The desk study returned numerous records of notable bird species within the Study Area, including hobby, Mediterranean gull, kingfisher (listed on Greater London BAP and an Amber List species of Conservation Concern), and redwing. These species are listed on Schedule 1 of the Wildlife and Countryside Act 1981 (as amended). In addition, other records included skylark, lapwing and sand martin, all of which are identified as priority species in the UK BAP. However, no habitats suitable for supporting these species were recorded within the Highways Agency Boundary. 8.3.62 Desk study records for other BAP species include song thrush, starling and house sparrow. Both song thrush and house sparrow are also Species of Principal Importance for the Conservation of Biodiversity in England (under Section 41 of the Natural Environment and Rural Communities Act (NERC) 2006). 8.3.63 Incidental sightings of bird species were made during the field surveys. This included kingfisher with possible nesting burrows identified within the sand banks of Mimshall Brook. Full information on bird records for the study area can be found in Appendix D2. Terrestrial Invertebrates 8.3.64 Records of notable invertebrates including stag beetle, small heath butterfly and large heath butterfly were identified within the study area, particularly within the vicinity of Epping Forest. These are all UK BAP Priority species and deadwood invertebrates are included in the HABAP. The stag beetle is also protected under the Conservation (Natural Habitats, &c.) Regulations 2010 and listed on the UK, Hertfordshire, Essex and London BAPs. A white letter hairstreak butterfly was recorded incidentally during the walkover survey in the Foxhole Hill area in 2006 on the clockwise side of the M25, opposite New Cottage Farm. These are all identified as priority species in the UK BAP. 8.3.65 In general, habitats within the soft estate are not especially diverse in structure or plant species and are relatively recent in origin. Aquatic Invertebrates 8.3.66 White clawed crayfish are a UK BAP Priority species and are included in the HABAP. 8.3.67 There are records of white-clawed crayfish within the Lee Valley complex. However, consultation with the Environment Agency during the preparation of the EAR in 2007 concluded that this species is no longer likely to be present within the Study Area. This is due to the recent introduction of non-native crayfish and crayfish plague into many river catchments throughout England. 8.3.68 During the 2010 otter and water vole surveys watercourses around Junction 27 were assessed to offer potential habitat to support crayfish, particularly Hobbs Cross Stream and Garnish Hall
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Stream. However, the positive identification of signal crayfish on these watercourses means that there are unlikely to be white clawed crayfish present, due to crayfish plague or competition. 8.3.69 Therefore, crayfish are not considered any further in this assessment. 8.4 Value (Sensitivity) of Resource 8.4.1 Baseline information has been assessed against the criteria set out in Interim Advice Note (IAN) 130/10 Ecology and Nature Conservation: Criteria for Impact Assessment (Highways Agency, 2010). Table 8.5 shows the value of each resource with the potential to be associated with significant effects. All statutory sites within the study area and all non-statutory sites immediately adjacent to the scheme are included. Table 8.6 provides valuation of habitats and species known or potentially present within the scheme area.
Table 8.5 - Value of Statutory and Non-Statutory Designated Sites Site Name Distance from Project (m) Value Statutory Sites Lee Valley SPA and RAMSAR Site, 1,100 International which includes Turnford and (upstream) Cheshunt Pits SSSI Epping Forest SAC and SSSI Adjacent European Cornmills Stream and Old River Lea 900 (upstream) National SSSI Waltham Abbey SSSI 1,330 National Chingford Reservoirs SSSI 1,960 (downstream) National Non-statutory sites Fir and Pond Wood Nature Reserve Adjacent County CWS Oxleys Wood Complex LoWS Adjacent County Wash Lane CWS Adjacent County Wash Lane Common and Dancers Adjacent County Hill Common CWS The New River SMINC Adjacent County The Lower Lee Valley SMINC Adjacent County Green Lane and Brambly Shaw Adjacent County LoWS Copped Hall Green LoWS Adjacent County The Selvage LoWS Adjacent County
Table 8.6 - Value of Habitats and Species within Highways Agency boundary Site Name Description Value Habitats within the scheme area Woodland – Broad-leaved Small areas near J23 and J26 and adjacent to Local and mixed semi natural The Warren. woodland Woodland – Broad-leaved Majority of woodland within the scheme Negligible and mixed plantation boundary is of this type. Provides habitat
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Site Name Description Value woodland connectivity. Hedgerows, Hedgerow No species-rich hedgerows. Majority of trees Negligible trees and scattered trees are semi-mature or immature. Scrub – dense and Significant areas of scrub present within the Negligible scattered scheme boundary. Grassland Semi-improved neutral grasslands Negligible widespread, one of the largest habitats within the HA boundary. Predominantly species- poor. Occasional amenity grassland areas. Aquatic Habitats A number of rivers and other watercourses Local pass under the existing M25 (mostly via culverts), one river runs parallel. Some of the rivers connect or form part of designated sites. Two canals cross the M25 (The New River by Junction 25, which passes over the motorway in an aqueduct) and the River Lea Navigation (flows through an underpass). Other habitats Other habitat types recorded within the HA Negligible boundary include ephemeral vegetation, tall ruderal herbs, introduced shrub and bare ground. Notable plants within the scheme area Yellow vetchling Found on verge adjacent to Gardners Local Underbridge between Junction 26 and 27 on the anticlockwise side. Nationally scarce but relatively widespread in the south east of England and population on verge is localised to a small area. Species known or potentially present in the scheme area Badgers using the HA soft Two setts confirmed. One within 30m and one Negligible estate within 150m of the scheme. Suitable habitat within scheme for badgers, so likely that they use the habitats within the soft estate, particularly in areas close to these setts. Nationally protected, listed on the London BAP on the Highway Agency‟s BAP as being particularly susceptible to road impacts. Widespread in the UK and locally. Bats using the HA soft No roosts confirmed, but bridges and trees with Local estate potential roosting features identified. All native bats are European Protected species. The woodland and scrub habitats on the verges and the mixture of arable fields, hedgerows, woodland edges and watercourses in the adjacent land provide commuting and foraging habitat of local value for bats. Dormice using the HA soft Some habitat within the HA verge have been Negligible, but estate identified as suitable to support dormice. No mitigation is areas with confirmed dormice present. proposed due to Dormice are a European Protected species. legal protection of dormice and theoretical potential for them to be present but undetected
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Site Name Description Value Otters and water voles Potential presence of otters using Hobbs Local using watercourses Cross stream within 500m of J27. Water crossing the scheme voles have been recorded on Mimmshall Brook (north) and in the local area in the past. Otters have European protection and water voles are protected by UK law. Great crested newts using No ponds are present on the soft estate. All Local the HA soft estate habitats present are considered suitable terrestrial habitat. All habitat which is within 500m of ponds known or assumed to be used by great crested newts is considered as potentially containing great crested newts. For ponds where conclusive newt surveys could not be completed, a precautionary approach has been employed and it is assumed that newts are present. Although the species has European protection, individuals are likely to represent a small proportion of the populations in the local area. Reptiles using the HA soft Mixture of grassland, scrub and woodland Local estate habitats suitable for reptiles. Common lizard found in low numbers at three survey sites and grass snakes found in low numbers at a further two survey sites. For areas of medium or high suitability for reptiles where conclusive surveys were not possible, a precautionary approach has been employed and it is assumed that reptiles are present. Although species has national protection, low numbers of individuals are considered to be present, representing a small proportion of the populations in the local area. Birds using the HA soft Woodland, scrub and trees provide suitable Negligible estate habitat for common species of breeding wild birds, all of which, and their occupied nests, are protected by UK law. Terrestrial Invertebrates Habitats likely to support common invertebrate Negligible using the HA soft estate species. 8.5 Regulatory/Policy Framework National Policy 8.5.1 The scheme has been assessed in terms of national, regional and local level planning policies and national legislation. Appendix D1 provides details of the relevant legislative and policy framework for relevant protected species and habitats, i.e. those that have been recorded in previous surveys, or protected species for which suitable habitat is recorded. A summary of key legislation and policy is provided below: Natural Environment & Rural Communities Act, 2006; National Planning Policy Framework 2012, March 2012, Policy 11: Conserving and Enhancing the Natural Environment;Wildlife and Countryside Act 1981 (as amended by the Countryside & Rights of Way Act, 2000; Conservation of Habitats and Species Regulations 2010; The Protection of Badgers Act, 1992;
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Hedgerow Regulations, 1997; and The UK and relevant local (Hertfordshire, London and Essex) Biodiversity Action Plans (BAPs). 8.5.2 In addition, the Highways Agency BAP, or HABAP, is part of a long-term strategy for the conservation of habitats and species on the motorway and trunk road verges of England. The overarching aim of the HABAP is to help the Agency achieve its objectives for conserving and, where possible, enhancing biodiversity National Planning Policy Framework 8.5.3 Policy 11: Conserving and enhancing the natural environment replaces PPS9: Biodiversity and Geological Conservation and states the planning system should contribute to and enhance the natural and local environment by, inter alia: • Protecting and enhancing valued landscapes, geological conservation interests and soils. • Recognising the wider benefits of ecosystem services. • Minimising impacts on biodiversity and providing net gains in biodiversity where possible, contributing to the Government‟s commitment to halt the overall decline in biodiversity, including by establishing coherent ecological networks that are more resilient to current and future pressures. 8.5.4 With the new NPPF there is a presumption in favour of sustainable development (paragraph 14). To minimise impacts on biodiversity and geodiversity, Policy 11 guides local authorities when determining planning applications to conserve and enhance biodiversity by applying the following principles (paragraph 118): • If significant harm resulting from a development cannot be avoided (through locating on an alternative site with less harmful impacts), adequately mitigated, or, as a last resort, compensated for, then planning permission should be refused; • Proposed development on land within or outside a Site of Special Scientific Interest likely to have an adverse effect on a Site of Special Scientific Interest (either individually or in combination with other developments) should not normally be permitted unless the benefits of the development, at this site, clearly outweigh both the impacts that it is likely to have on the features of the site that make it of special scientific interest and any broader impacts on the national network of Sites of Special Scientific Interest; • Development proposals where the primary objective is to conserve or enhance biodiversity should be permitted; • Opportunities to incorporate biodiversity in and around developments should be encouraged; • Planning permission should be refused for development resulting in the loss or deterioration of irreplaceable habitats, including ancient woodland and the loss of aged or veteran trees found outside ancient woodland, unless the need for, and benefits of, the development in that location clearly outweigh the loss; and • Potential Special Protection Areas (pSPA) and possible Special Areas of Conservation (pSAC), listed or proposed Ramsar Sites and sites identified, or required, as compensatory measures for adverse effects should be given the same protection as European sites. Local Policy Hertsmere Borough Council Local Plan 8.5.5 Hertsmere Borough Local Plan (Hertsmere Borough Council, 2003) includes the following relevant policies: 8.5.6 Policy E1: Sites of Special Scientific Interest
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“In the interest of protecting nationally important scientific sites, development will not be permitted on the Sites of Special Scientific Interest shown on the Proposals Map, nor on others which English Nature may subsequently notify, nor on land adjoining or adjacent to such areas where it would be likely to have an adverse effect on the SSSI, unless the Council is satisfied that the development will not have damaging impacts on wildlife habitats or important physical features. Any proposals for development will be subject to special scrutiny and referred to English Nature for advice.” 8.5.7 Policy E2: Nature Conservation Sites – Protection “Development which could have an adverse effect on a Local Nature Reserve, a Wildlife Site or a Regionally Important Geological/Geomorphological Site, as identified on the Proposals Map or as identified by any future studies and published as non-statutory guidance, will not be permitted unless it can be clearly demonstrated that there are reasons for the proposal which outweigh the need to safeguard the nature conservation or geological value of the site. Where proposed development could have an adverse impact on such a site the submission of an environmental statement will be required with the application. Where such development is permitted the Council will seek to ensure that any necessary measures are taken to mitigate and compensate for any damage caused. Such measures must be within the control of the developer and subsequent site owner(s) or operator(s).” 8.5.8 Policy E3: Species Protection “Planning permission will not be granted for development which could have an adverse impact on badgers or species protected by Schedules 1, 5 or 8 of the Wildlife and Countryside Act 1981, as amended, unless it can be clearly demonstrated that there are reasons for the proposal which outweigh the need to maintain the unaltered and undisturbed habitat of the affected species. Where proposed development could have an adverse impact on such species the submission of an environmental statement will be required with the application. Where such development is permitted the Council will seek to ensure that any necessary measures are taken to: (i) facilitate the survival of the species; and (ii) minimise disturbance; and (iii) provide adequate alternative habitat(s) to sustain at least the current levels of population. Such measures must be within the control of the developer and subsequent site owner(s) or operator(s).” 8.5.9 Policy E4: Features of Major Importance for Nature Conservation “Developments which are likely to adversely affect any features listed below which are of major importance for wild flora and fauna will only be permitted if it can be shown that the reasons for the development outweigh the need to retain the feature(s). In such instances either suitable mitigation, reinstatement or replacement of the feature(s) will be sought and the ability or otherwise to do this will be considered as part of the planning decision. Such measures must be within the control of the developer and subsequent site owner(s) or operator(s). In appropriate instances the submission of an environmental statement will be required to accompany such an application. List of Features: Hedgerows, linear tree belts, plantations and woods, green lanes, river corridors (including banks), ponds (excluding private garden ponds) and lakes, urban wildlife corridors / green links or chains.” 8.5.10 Policy E6: Nature Conservation – Opportunities Arising from Development “Where landscaping schemes are sought in connection with a development proposal the incorporation of measures to promote habitat creation or enhancement will be encouraged. Where
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possible and appropriate, native species of plants, shrubs and trees should be used to foster wildlife interest. Ideally such planting should be of local provenance where this is possible.” 8.5.11 Policy E7: Trees and Hedgerows – Protection and Retention “Tree Preservation Orders will be made to ensure that existing trees, or groups of trees, which are healthy and contribute to the amenity of the area, are retained and protected. When permission is given to remove existing trees subject to Tree Preservation Orders replacement planting will be required. The Council will also use its powers under the Hedgerow Regulations 1997 (and any successive legislation) to protect hedgerows. Planning permission will be refused for development which would result in the loss, or likely loss, of any healthy trees and/or hedgerows which make a valuable contribution to the amenity of the area in which they are located unless the benefits of the proposed development outweigh the amenity value of the tree and/or hedgerow. If development is approved which would result in the removal of trees and/or hedgerows, equivalent and appropriate replacement planting will be required.” 8.5.12 Policy E8: Trees, Hedgerows and Development “On development sites where existing trees and/or hedgerows are to be retained and/or new planting provided it will be a requirement that:- (i) the proposals provide sufficient space between trees and/or hedgerows and buildings, roads/footpaths and parking areas to enable the implementation of the development to take place without affecting the existing and proposed landscape features and ensure that their health is not endangered by water deprivation; (ii) existing trees, which are removed to enable the development to take place, are replaced by two trees for every one removed within the landscape scheme for the site. Adequate attention shall be given to the species and the spaces required for these trees to mature within the overall layout of the development. Appropriate replacement planting will also be required for any hedgerows which are removed to enable the development to take place; (iii) the location of all site works including storage of materials and the location of services (i.e. gas, electricity, water, drainage, communications cables) shall not directly or indirectly damage or destroy any trees or hedges to be retained; and (iv) adequate protection shall be provided throughout the period of construction to protect trunks, root systems and limbs from damage. Where appropriate, details of fencing or other protection measures will be required for approval before any works commence on site. Development proposals should ensure that sufficient land is provided for additional planting and landscaping. Existing wildlife habitats, ecological, topographical and landscape features; including trees, hedges, shrubs, water features and walls; should be retained and utilised in the new scheme.” Hertsmere Revised Core Strategy Consultation Draft 8.5.13 Hertsmere Local Development Framework Development Plan Document Revised Core Strategy Consultation Draft (Hertsmere Borough Council, 2010) includes the following relevant policy: Policy CS12 Protection and enhancement of the natural environment “All development proposals must conserve and enhance the natural environment of the Borough, including biodiversity, protected trees, landscape character and sites of ecological and geological value, in order to maintain and improve environmental quality. Proposals should provide opportunities for habitat creation and enhancement throughout the life of a development. There will be a presumption against inappropriate development and other development, which causes harm to the openness and appearance of the Green Belt, as defined in PPG2 (Green Belts) and in the case of the highest quality agricultural land (Grades 1, 2 and 3a) and Preferred Areas of mineral extraction, proposals will only be permitted where there is no likelihood of the land being sterilised. Strategic gaps in the Green Belt between Bushey and Watford and Bushey and
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Stanmore will be maintained within which any limited development, deemed acceptable in the Green Belt, should serve to retain the separation between the towns.” Welwyn Hatfield District Plan 8.5.14 Welwyn Hatfield District Plan (Welwyn Hatfield Borough Council, 2005) includes the following relevant policies: 8.5.15 Policy R11: Biodiversity and Development “All new development will be required to demonstrate how it would contribute positively to the biodiversity of the site by; (i) The retention and enhancement of the natural features of the site; (ii) The promotion of natural areas and wildlife corridors where appropriate as part of the design; (iii) The translocation of habitats where necessary, where it can be demonstrated that the habitat or species concerned cannot be successfully accommodated within the development; (iv) The use of locally native species in planting in accordance with Policy D8 Landscaping; (v) Helping meet priorities/targets set out in the Local Biodiversity Action Plan.” 8.5.16 Policy R13: Sites of Special Scientific Interest “Proposals for development in or likely to affect Sites of Special Scientific Interest will be subject to special scrutiny. Where such development including that on land adjoining or adjacent to the sites may have an adverse effect, directly or indirectly, on the SSSI it will not be permitted unless the reasons for the development clearly outweigh the nature conservation value of the site itself and the national policy to safeguard the national network of such sites. Where development is permitted the Council will consider the use of conditions and/or planning obligations to ensure the protection and enhancement of the site‟s nature conservation interest.” 8.5.17 Policy R15: Wildlife Sites “Planning permission will not be granted for any development which would have an adverse effect on Wildlife Sites or Regionally Important Geological/Geomorphological Sites unless: (i) It can be demonstrated that the reasons for development outweigh the need to safeguard the biodiversity of the site; and (ii) Measures are taken to mitigate the effect of the development, to compensate for any residual adverse effects and to reinstate the nature conservation value of the site.” 8.5.18 Policy R17: Trees, Woodland and Hedgerows “The Council will seek the protection and retention of existing trees, hedgerows and woodland by the use of planning conditions, section 106 agreements, hedgerow retention notices and tree preservation orders where applicable. New development will be required to incorporate wherever appropriate new planting with locally native species and should be in accordance with Policy D8 Landscaping.” Borough of Broxbourne Local Plan 8.5.19 The borough of Broxbourne Local Plan (Borough of Broxbourne, 2005) includes the following relevant policies: 8.5.20 GBC 18 Protection of Internationally Important Wildlife Sites: “Development that would harm the nature conservation or geological interest of an internationally important wildlife site will not be permitted unless; I) It is required in connection with the management or conservation of the site; and II) There is a clear need to support the development in the public interest; and
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III) There is no less environmentally damaging solution.” 8.5.21 GBC 19 Protection for sites of wildlife and nature interest: “I) Development will not be permitted if it would have an adverse effect on: a) Special Areas of Conservation b) Special Protection Areas (SPAs) c) Sites of Special Scientific Interest (SSSI) d) Local Wildlife Sites e) Local Nature Reserves Unless the need for the development outweighs its nature conservation or geological value. II) Where necessary, any environmental impact assessment (EIA) should identify the extent of any harm to the nature conservation or geological interest of the site and any remedial measures to mitigate the impact of development, green belt and countryside and the means of implementation of such measures through planning conditions and/or planning obligations.” 8.5.22 GBC20 Protected Species: “I) Planning permission will not be granted for development which would have a material adverse impact on any species afforded protection by the Wildlife and Countryside Act 1981 (As amended). II) Where development is permitted which may have an impact on a protected species, the council will impose planning conditions to: a) Facilitate the survival of individual members of the species; b) Require disturbance to habitats to be minimized; c) Provide adequate alternative habitats to sustain current levels of population.” Broxbourne Local Development Framework Submission Core Strategy 8.5.23 The Broxbourne Local Development Framework Submission Core Strategy (Borough of Broxbourne, 2010) includes the following relevant policy: 8.5.24 Policy CS8 Environment includes the following text: “All sites in and adjoining the borough which are protected by the planning system or of important landscape, wildlife, scientific and/or archaeological value will be conserved and enhanced in accordance with national guidance and local objectives. “ The Enfield Plan Core Strategy 2010-2025 8.5.25 The Enfield Plan Core Strategy 2010-2025 (Enfield Council, 2010) was adopted in November 2010 8.5.26 Core Policy 36 Biodiversity includes the following: “The Council will seek to protect, enhance, restore or add to biodiversity interests within the Borough, including parks, playing fields and other sports spaces, green corridors, waterways, sites, habitats and species identified at a european, national, London or local level as being of importance for nature conservation by: Continuing to protect, restore, and enhance sites, habitats and species identified for their biodiversity importance at the national, London, or borough level. The Development Management Document will set out criteria to assess development proposals that are likely to have an adverse ecological impact.
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Epping Forest District Local Plan 8.5.27 Epping Forest District Local Plan and Alterations (Epping Forest District Council, 1998 and 2006) includes the following relevant policies: 8.5.28 Policy NC1: SPAs, SACs and SSSIs: “The Council will refuse planning permission for any development or land use change which could directly or indirectly destroy or adversely affect a Site of Special Scientific Interest. The Council will comply with the U.K.'s international obligations for those SSSIs designated or proposed as Special Protection Areas or Special Areas of Conservation.” 8.5.29 Policy NC2: County Wildlife Sites: “Development or land use change which could directly or indirectly destroy or have an adverse effect upon a County Wildlife Site will be refused unless it can be demonstrated that the reasons for the proposal clearly outweigh the need to safeguard the intrinsic nature conservation value of the site or feature.” 8.5.30 Policy NC3: Replacement of lost habitat: “In cases where a County Wildlife Site will be harmed by, or lost to, development, the Council will expect satisfactory arrangements to be made for an alternative habitat of at least equivalent wildlife value.” 8.5.31 Policy NC4 Protection of Established Habitat: “Development proposals will be expected to make adequate provision for the protection, enhancement and suitable management of established habitats of local significance for wildlife. Such provision may be more stringent when there are known to be protected species either on the site or likely to be affected by the development.” 8.5.32 Policy NC5 Promotion of nature conservation schemes: “The Council will encourage owners and occupiers of land to participate in schemes which promote the aims of nature conservation by: (i) adopting less intensive forms of land management; (ii) re-introducing traditional management techniques for existing wildlife habitats; and (iii) creating new habitats.” 8.6 Design, Mitigation and Enhancement Measures 8.6.1 This section describes measures that have been undertaken to avoid or reduce potential adverse ecological effects that could arise from the scheme. The specific measures are described below for each of the key receptors. As a general principle, four strategies were used: Avoidance of the most sensitive ecological features or reduction of adverse effects through design of the scheme and sensitive programming of works; Measures to minimise risks of harm to individual animals of legally protected species during site clearance and construction; Compensation measures to offset residual impacts remaining following the application of mitigation measures; and Incorporation of enhancement measures. 8.6.2 Locations of ducting for cabling, construction compounds, access tracks, storage areas and other construction related activities are not yet known and therefore detailed mitigation measures for these have not been included and will need to be developed as the detailed design progresses.
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8.6.3 During construction, specific measures will be outlined in a detailed Construction Environmental Management Plan (CEMP) which will be produced by the DBFO Contractor. Issues covered by the CEMP will include: Timing of construction activities to avoid seasonal constraints and advance works to minimise the impact of construction phase activities; Use of areas of low quality habitat and avoidance of sensitive areas for construction compounds, storage areas and other associated construction activities; Where works affect or have the potential to affect a particular protected or notable species, appropriate specific site clearance methodologies and licences would be put in place before works commence; Use of temporary fencing/barriers/markers to limit access and thus disturbance to sensitive areas. Such areas would be identified and delineated in advance of on-site works by a suitably qualified ecologist; Appropriate implementation and control of lighting during construction. Any night-time working undertaken in key areas will be restricted at certain times of the year when certain species, e.g. bats, would not be active; Where necessary, supervision of works by a suitably qualified ecologist; The collection, storage and re-use of topsoil or turf from species-rich areas for habitat creation strategies; Enhancement of existing habitats using sympathetic and targeted management regimes to increase carrying capacity for wildlife; Measures to control dust to prevent deposition on habitats and sites adjacent to works, including those within designated sites. Typical measures are provided in Section 5.6 within the Air Quality chapter; Designated secure and safe areas for storage of hazardous chemicals and materials; and Implementation of strict pollution control measures to prevent any impacts on watercourses. General Mitigation 8.6.4 Impacts on designated sites, sensitive habitats and areas likely to contain protected or notable species have been avoided where possible in the design, by locating structures away from these receptors. 8.6.5 The design and construction working methods are such that site clearance is kept to a minimum. For example installation of gantries and ERAs will be carried out from the hard shoulder to minimise site clearance for access. In areas where the verge is at grade the clearance area required is likely to be limited to at worst 1-2m working space beyond the hard shoulder, but where there are cuttings or embankments additional earthworks are likely to be required resulting in a larger clearance areas of up to 6m from the hard shoulder. A retaining wall up to 6m high will be built along the westbound exit from Bell Common tunnel. It is expected that this will be accommodated within the land take required for the widening works and it will be within the Highways boundary. The design details have yet to be confirmed. Working areas will be kept to a minimum and sensitive areas avoided where possible. 8.6.6 The extent of new communications ducting and maintenance access footways is currently unknown. It has been assumed that new ducting will be required along the length of the scheme along one side of the carriageway and that installation of new ducting is likely to involve the clearance of up to 3m of verge habitat. Following construction, this 3m swathe is likely to become a footway used for maintenance access, resulting in the permanent loss of this habitat.
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8.6.7 In areas where access will be required for maintenance, maintenance footpaths and areas of maintenance hardstanding may be required. The extent of these is currently unknown. It is anticipated that maintenance footpaths are likely to be 1m in width and be set back from the safety barrier by at least 1.5m where present. Where these are required there will be additional permanent loss of verge habitat. 8.6.8 On the opposite side of the carriageway from where communications ducting is laid, a maintenance access footway is likely to be required. This is likely to be 1m in width and be set back from the safety barrier by at least 1.5m along the length of the scheme, resulting in the permanent loss of a swathe of up to 3m of verge habitat adjacent to the hard shoulder. 8.6.9 Exact locations for ducting and footways will be confirmed during detailed design. Ducting for communications will re-use as much of the existing ducting as possible and areas of clearance for ducting and footways will avoid sensitive areas and be minimised to prevent loss of verge habitat where possible. 8.6.10 Details of the scheme and construction methods as far as they are known at this stage are included in Chapter 2 and illustrated in Figure 2.1. 8.6.11 Advanced ecological works are required prior to commencement of construction. Vegetation clearance, erection of protective fencing, and relocation or translocation of protected or notable species will be undertaken where necessary. Preparation of receptor sites may be required, which would be determined by a suitably qualified ecologist prior to the relocation/translocation of any species. Licences will be obtained from Natural England, as appropriate, prior to commencement of works. Once the proposed construction working areas, season and timings of works are known it may be necessary to obtain mitigation licences for great crested newt and bats. A badger development licence may also be required prior to construction. 8.6.12 Landscape planting proposals will be designed in consultation with a suitably qualified ecologist to ensure opportunities for creating suitable habitats and linkages are fully realised. 8.6.13 Prior to the start of site works, an update walkover survey will be undertaken to assess whether habitat suitability for protected species has altered in any areas, as mitigation proposals would need to take account of such changes. If deemed necessary during the walkover, further survey work may be required prior to construction, where there are no access or safety limitations. If survey is not possible in these areas for access or safety reasons, precautionary mitigation may be required. Statutory and Non-statutory Designated Sites 8.6.14 During construction works, measures undertaken to control dust outlined above would mitigate any potential dust impacts on any designated sites adjacent to the scheme. 8.6.15 Fencing will be used to prevent accidental incursion by the workforce into adjacent designated sites, where required. Statutory Designated Sites Epping Forest SAC/SSSI 8.6.16 Natural England outlined concerns regarding air quality impacts on Epping Forest SAC during the operational phase and during the construction phase, in particular the possibility that congestion resulting from widening works in the vicinity of Epping Forest may result in a significant increase in traffic using roads through the SAC. Particular consideration was given to these issues during air quality assessment. 8.6.17 Measures to regulate traffic during construction will be outlined in the CEMP (Construction Environmental Management Plan). This would include keeping structures away from the SAC and maintaining a buffer strip of vegetation where possible. The traffic management arrangements for ALR are very different to those considered in the previous schemes, with less construction in ALR and thus less residence time in any one section of the scheme (at present it is estimated that
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works between chainages 50400-63100 will take approximately 39 weeks), but the actual time spent along the Bell Common Tunnel areas adjacent to Epping Forest SAC are likely to be significantly less than that therefore reducing the likelihood of rat running through the forest. Traffic management measures will be employed during construction to further reduce the risk of rat running and this will be monitored during construction. 8.6.18 Other features for which this SAC is designated include Stag beetles. Stag beetles are resident within wet and decaying wood (stumps, branches) for much of its lifecycle which are generally situated away from the road. Therefore, due to their distance from the scheme and the nature of the proposed works, these features are unlikely to be affected and no mitigation is required. 8.6.19 The potential impacts on Epping Forest SAC have been assessed separately through an Assessment of Impacts on European Designated Sites (AIES) (Appendix A). Chingford Reservoirs SSSI 8.6.20 Chingford Reservoirs SSSI is located approximately 1.96km to the south of the scheme, but is downstream and connected via the River Lee. This SSSI could therefore be potentially negatively affected by any pollution incident resulting from the proposed works. 8.6.21 To minimise this risk, maintenance access footways will be formed of a porous surface and will not increase the area of hardstanding. The creation of ERAs represents a minor increase in the hardstanding in the scheme area. Drainage for ERAs will collect water in one or two manholes and discharge into existing networks at a slow rate so as to not overload the existing networks. Strict pollution control measures will also be put in place to control any pollution created by vehicles in ERAs as detailed in Section 14.6 Road Drainage and the Water Environment. This would mitigate any potential impacts to the SSSI and any other watercourses or waterbodies. Other Statutory Designated sites 8.6.22 Lee Valley SPA/RAMSAR site (which includes Turnford and Cheshunt Pits SSSI) is 1,100m upstream and Cornmills Stream and Old River Lea SSSI is 900m upstream from watercourses flowing under the M25. Waltham Abbey SSSI is 1,330m from the scheme. None of these designated sites are considered likely to be affected by the proposed works due to their distance and locations upstream. Therefore, no specific mitigation relating to these SSSIs is required. 8.6.23 Curtismill Green SSSI and Water End Swallow Holes SSSI were included as receptors in the air quality assessment as they were within 200m of the road network to assess air quality impacts on these receptors. 8.6.24 The full results of this assessment can be found in the air quality chapter 5. Curtismill Green and Water End Swallow Hole SSSIs are not considered likely to be affected by the proposed works due to the nature of the sites and their distance from the Project (Curtismill Green SSSI is located on the south side of the M25 between J27 and J28, Water End Swallow Holes SSSI is approximately 60m to the east of the A1(M) between Junctions 1 and 2 and outside of the study area. Therefore, no specific mitigation relating to these SSSIs is required. Non Statutory Designated sites 8.6.25 Nine of the twenty-four non-statutory designated sites within 500m of the scheme are located immediately adjacent to the HA boundary. All habitat loss and disturbance is restricted to land within the HA boundary, including temporary clearance for construction. Additionally, where designated sites are adjacent, ERAs, signs, signals and gantries have been located to ensure that, wherever possible, there is a habitat buffer between the structure and the adjacent site. 8.6.26 A cantilever ADS is proposed at chainage 52860 anti-clockwise. This is adjacent to The Lower Lee Valley SMINC where it may not be possible to retain a buffer strip between the ADS and the SMINC boundary due to the narrow verge at this location. However, retention of the habitat within the SMINC will maintain habitat connectivity and prevent fragmentation.
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8.6.27 The cantilever signal at chainage 43160 clockwise is adjacent to Fir and Pond Wood Nature Reserve CWS. A buffer strip of vegetation will be retained on the verge at this location and retention of the habitat within the CWS will maintain habitat connectivity and prevent fragmentation. 8.6.28 Care will be taken to minimise the area of clearance needed at these locations. 8.6.29 Clearance of vegetation along the 3m swathe closest to the carriageway for communication ducting and maintenance access footways will result in the loss of the buffering strip of habitat currently present where the verge is narrow. However, habitat connectivity will be maintained due to the presence of the retained adjacent habitats and the 3m swathe would not include any land within a designated site. 8.6.30 A small number of ditches and watercourses pass under the highway connecting with designated sites that lie immediately adjacent to the HA boundary. Maintenance access footways will be formed of a porous surface and will not increase the area of hardstanding. The creation of ERAs represents a minor increase in the hardstanding in the scheme area. Drainage for ERAs will collect water in one or two manholes and discharge into existing networks at a slow rate so as to not overload the existing networks. This would mitigate any potential impacts on non-statutory designated watercourses crossing under the scheme. 8.6.31 The implementation of strict pollution control measures, as described in the Chapter 13 Road Drainage and the Water Environment will prevent any impacts on watercourses or waterbodies. 8.6.32 Retained areas of habitat and areas temporarily affected during construction would benefit from enhancement following scheme completion including targeted re-planting and reseeding (with locally sourced, native species-rich planting mixes). Where areas of soft estate to be affected by the scheme are wide enough, habitat buffer strips will be maintained ensuring the integrity of the verge as a corridor and avoiding fragmentation and isolation of the areas not to be affected. These will be clearly shown on plans and marked out on site prior to construction. Habitats 8.6.33 Habitats within the soft estate to be affected by the project are primarily comprised of scrub (scattered, continuous and dense), grassland (semi-improved and neutral), and woodland (broadleaved plantation, mixed plantation, and broad-leaved semi-natural). Habitat loss will be kept to a minimum and encroachment onto adjacent habitat will be avoided by accurately fencing the works area. 8.6.34 Loss of habitat in the areas to be affected cannot be easily compensated for within the soft estate, as creation of one habitat type as mitigation would result in the loss of another. Some compensation can be provided through habitat enhancement. Retained areas of habitat and areas temporarily affected during construction would benefit from enhancement following scheme completion including targeted re-planting and reseeding (with locally sourced, native species-rich planting mixes) and/or the collection, storage and re-use of topsoil or turf from species-rich areas. Features of interest, such as rubble piles and log piles will also be created. 8.6.35 Where areas of soft estate to be affected by the scheme are wide enough, habitat buffer strips will be maintained ensuring the integrity of the verge as a corridor and avoiding fragmentation and isolation of the areas not to be affected. These will be clearly shown on plans and marked out on site prior to construction. In areas where the verge is narrow and vegetation removal for installation of communications ducting and maintenance access footways results in the removal of all vegetation along the verge, additional planting to maintain connectivity is likely to be required, particularly in areas where protected species are present and/or where adjacent habitats are not available to provide connectivity. Watercourses 8.6.36 The proposals do not involve any modification of culverts and watercourses within the scheme area. Adjacent watercourses would be safeguarded from pollution, as described above.
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Non Native Invasive Species 8.6.37 Japanese knotweed, Himalayan balsam, rhododendron and parrots feather were recorded during the Phase 1 Habitat Survey within the study area. On the HA verge this included Japanese knotweed at approximate chainages 37000 and 38900 anticlockwise. The full extent of invasive species within the Scheme requiring mitigation prior to site clearance will be re-surveyed before construction to ensure no new stands of Japanese knotweed have appeared and that previously eradicated stands have not regrown. Although not included within Schedule 9 of the Wildlife and Countryside Act (as amended), the resurvey will also include locating areas where goat‟s rue and michaelmas daisy are present, following Natural England‟s comments in response to the EAR Scoping Report. This re-survey will be included within the Construction Environmental Management Plan (CEMP) and dealt with appropriately in line with best practice. Protected and Notable Species Notable Plants 8.6.38 The nationally scarce yellow vetchling has been recorded as present at Ramney Marsh, within the Lower Lee Valley SMINC adjacent to the anticlockwise carriageway between Ramney Marsh Underbridge (chainage 52600) and the River Lee Underbridge (chainage 53200) and on the verge adjacent to Gardners Underbridge at chainage 62280. As a result of widening to the west of Junction 27 and the installation of maintenance access footways, part of the verge area supporting yellow vetchling will be permanently lost and part may be temporarily lost during construction. To prevent encroachment into the areas where yellow vetchling habitat will be retained, the construction works area will be clearly demarcated with protective fencing. Following construction, the areas of disturbed ground which previously formed the works area will be sown with a native grass and wildflower species mix with yellow vetchling seed, ideally collected from the habitat within the Highways Estate, in order to reinstate this species. If on-site collection is not possible, native seed from a local source would be used. Adjacent areas of suitable verge habitat will also be seeded in order to compensate for the areas of permanent loss. Mammals Badgers 8.6.39 One badger sett is located within 30m of a proposed cantilever signal. In addition, ducting or maintenance access footway construction is likely to be necessary within the verge. It is possible that disturbance could occur to badgers using the sett. Once the exact location of works in this area is known, a suitably qualified ecologist will assess the potential impacts on the sett and any necessary licensing and mitigation will be undertaken. 8.6.40 Another badger sett is located in an area where it is understood that it lies outside the proposed limit of works. The impacts on this sett will need to be reassessed once the final location of all ducting, construction working areas, storage areas or other construction related activities are known. 8.6.41 A full pre-construction re-survey will be carried out, including a careful search of dense areas of scrub directly affected by the proposals, in order to confirm the absence of additional badger setts. It is possible that a small or inactive sett may remain undetected or a new sett could be dug prior to construction. This survey will include a check of setts recorded as inactive during the Phase 1 Habitat Survey to establish their current status, and setts adjacent to the scheme which could be disturbed by the proposed works. If the pre-construction badger survey identifies any badger setts which will be affected by the proposals a disturbance badger licence will need to be obtained from Natural England. 8.6.42 Steep-sided excavations would present a trapping or injury hazard and will therefore contain a means of escape or be covered at night.
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Deer 8.6.43 Consideration will be given to providing mitigation for deer as part of the proposed works. Although not a protected species, the role of deer in road traffic accidents means that measures will be undertaken to discourage deer from crossing the carriageway. Such mitigation would include deer fencing at locations where deer casualties have been recorded, and where woodland habitats are located adjacent to the HA Boundary. A suitably qualified ecologist will assess such locations and advise on appropriate mitigation. Dormice 8.6.44 No dormice have been found in baseline surveys. It is theoretically possible that dormice may be present, in woodland and scrub habitats within the HA boundary, but remain undetected by surveys, particularly where these habitats link to woodland. Natural England, in their response to the EAR Scoping Report, has recommended that, “irrespective of survey results, appropriate mitigation measures (such as ensuring ecological supervision of all tree/scrub/hedge removal) should be put in place”. 8.6.45 The need for advance mitigation will be reviewed within the scheme area wherever works are necessary within potential dormouse habitat. Such mitigation would depend upon the extent of works and vegetation clearance required and the suitability of the habitats affected. Where works are in areas considered likely to support dormice but their presence has not been confirmed during the surveys, a Precautionary Method of Working (PMW) will be employed during the works to minimise the risk of offence being committed should dormouse be present within the works area. Clearance in these areas will be carried out in accordance with current best practice (Bright, Morris & Mitchell-Jones, 2006). The mitigation will include sensitive timings of works, habitat management, hand search and ecological watching brief where appropriate. Detailed mitigation will be developed once the programme is finalised and the extent of clearance areas for ducting and for construction have been defined. 8.6.46 In order to compensate for the loss of areas of potential dormouse habitat, trees/shrubs will be planted to link up areas of habitat which are fragmented as a result of habitat loss. Where possible, areas of trees/shrubs removed during construction will be replanted in order to maintain habitat connectivity on scheme completion. Bats 8.6.47 Bats have been recorded as foraging within the HA Boundary and adjacent to it. In addition, bridges along the route are considered to be used as crossing points by bats. Although there are no works proposed to the bridges, vegetation clearance for gantries, ERAs, ducting, footways or other construction related activities close to the bridges could result in the fragmentation of commuting routes and crossing points. In these areas particular care will be taken to minimise any vegetation clearance, avoid night-time working and lighting. 8.6.48 Areas of particular sensitivity for bats (i.e. those where bat activity was recorded, where barbastelles have been reported nearby and areas of high suitability/connecting habitats) are: Between chainage 37600 and chainage 38600 (clockwise carriageway) near J23 where high activity was recorded; Between chainage 41300 and chainage 42000 (clockwise and anticlockwise carriageways) near J24 where high activity was recorded; Between chainage 43300 and chainage 44500 (clockwise and anticlockwise carriageways), where low bat activity; Between chainage 45100 and chainage 45600 (clockwise and anticlockwise carriageways) where low bat activity has been recorded; Between chainage 46300 and chainage 47400 (clockwise and anticlockwise carriageways) where high bat activity has been recorded;
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Between chainage 57500 and chainage 57900 (anticlockwise carriageways) where low bat activity has been recorded; Between chainage 58800 and chainage 60400 (clockwise and anticlockwise carriageways) where bat activity has been reported, including barbastelles in the desk study; and Between chainage 60900 and chainage 61700 (clockwise and anticlockwise carriageways) where high bat activity has been reported. 8.6.49 Additional lighting, noise and vibration during the construction phase could deter bats from emerging from roosts, foraging within the HA Boundary and crossing over the M25. Therefore, in these areas in particular night-time working will be kept to a minimum and where required, consideration will be given to carrying out works during times when bats are not active, for example during the winter months. Floodlighting (and possibly other forms of construction related lighting) has been shown to affect bat foraging behaviour and the use of roosts. Lighting during night time works will therefore be strictly controlled (e.g. avoidance of direct lighting of commuting/foraging habitats such as woodland, scrub, trees, minimising the duration of lighting, for example, by avoiding excessive lighting around the time that bats emerge from roosts and commute to feeding areas). Baffles will be used where necessary to reduce light spill from construction floodlights. In the unlikely event that a roost is confirmed, direct illumination will be avoided, as this could cause disruption to bat emergence times and/or cause bats to abandon the roost. 8.6.50 Other disturbances, such as noise and vibration during the construction phase will be strictly controlled and kept to a minimum. 8.6.51 In areas where permanent habitat loss is necessary, where possible a buffer strip of habitat will be maintained or returned upon scheme completion to ensure habitat links are maintained and fragmentation is avoided. In areas where the verge is narrow and vegetation removal for installation of communications ducting and maintenance access footways results in the removal of all vegetation along the verge, additional planting to maintain connectivity may be required, particularly in areas where adjacent habitats are not available to provide connectivity. 8.6.52 No new lighting is proposed for the main road and existing lighting will be retained unaltered unless replacement is required where there is widening. In order to minimise disturbance of bats and other wildlife using the verge habitats at night, the absence of lighting is preferable. The need for lighting of ERAs will be reviewed during the detailed design, but at the current time, it is anticipated that the ERAs will not be lit. 8.6.53 Trees in the vicinity of the works have been assessed for their potential to support bat roosts during the phase 1 habitat survey. Five trees with potential for roosting bats are adjacent to the HA boundary (Target notes 60, 163, 220, 597, 640 shown in Figures 3.1 to 3.17, Appendix D2). Once further information about locations of ducting, maintenance access footways, site compounds, access routes, storage areas, or other construction related areas are known, any trees to be affected will be re-assessed by a suitably qualified ecologist and it may be appropriate to undertake further surveys. If a roost is confirmed in a tree to be directly affected by the works, a Natural England licence would be obtained prior to the proposed works. Different species of bats have different roosting requirements at different times of the year. As a result, the appropriate mitigation would depend on the numbers and species of bats present. 8.6.54 No culverts, bridges or tunnels will be directly affected by the current design, so no mitigation is currently proposed in relation to these. Wherever possible, gantries have been located away from bridges/structures with the potential for roosting bats or features of interest for bats. Otter and Water Vole 8.6.55 The potential presence of water voles and otters was confirmed within the survey area on various watercourses along the scheme.
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8.6.56 There are no direct impacts or works affecting any of the watercourses located along the scheme. The proposals do not involve any modification of culverts, watercourses or waterbodies or outfalls. 8.6.57 Disturbance to migrating otters could occur where Hobbs Cross stream passes under the M25 and where potential otter signs have been recorded. Mitigation to minimise any disturbance to migrating otters travelling through the area will include the avoidance of night-time works. 8.6.58 Otters do not occupy every part of their territory all year round and so pre-construction surveys at watercourses, which are most likely to support otters (Watercourse 16 and 17, Hobbs Cross stream as shown in Figures 2.1 to 2.5 in Appendix D5), will be undertaken to establish presence/absence of occupied holt sites at time of construction. If otters are found to be present additional mitigation measures may be required and a licence obtained from Natural England. 8.6.59 Further areas will require additional otter surveys if the design of the scheme should change in a way that affects any watercourses, to ensure that the conditions have not changed. 8.6.60 As water voles have been recorded on Mimmshall Brook (north) and in the local area in the past a pre-construction survey will be carried out prior to works, to ensure that the conditions have not changed. 8.6.61 Impacts to watercourses through increased pollution from routine runoff and accidental spillages would be avoided by attenuation and pollution control measures as detailed above and within the Road Drainage and the Water Environment chapter of this report. 8.6.62 In addition, the measures outlined in the CEMP should be followed. Herptiles Great Crested Newts 8.6.63 Results of the surveys indicate that at least some elements and some areas of the scheme will require a European Protected Species Licence (EPSL) prior to the start of construction. The exact extent and nature of the licence will be considered by a suitably qualified ecologist and will take account of all design information including locations of compounds, access routes, storage areas, once these are confirmed. 8.6.64 The need for advanced mitigation would be reviewed within the scheme area wherever the presence of great crested newts is confirmed within 500 metres of an area subject to works activity. Such mitigation would depend upon the size of the population recorded and the suitability of the habitats affected. Where work would be within 500m of a GCN pond but an offence is considered unlikely and therefore a licence would not be required, a Precautionary Method of Working (PMW) will be employed as an alternative. 8.6.65 EPSL, where considered necessary, will require adherence to a strict mitigation method statement as per the English Nature Great Crested Newt Mitigation Guidelines (2001). Mitigation is likely to involve exclusion and translocation of newts prior to site clearance of suitable habitats, sensitive timings of works, habitat management, hand search and ecological watching brief where appropriate. Mitigation will be undertaken during spring, summer and early autumn when animals are active. 8.6.66 Where temporary works are confined to relatively discrete areas it is considered appropriate to move any great crested newts from the working areas (by translocation under EPSL as described above), locally to the areas of unaffected soft estate with suitable habitat. Translocation to a dedicated receptor site will only be necessary if large areas of verge habitat are affected where there is no available adjacent verge habitat to act as a receptor site. This may be applicable to areas where ducting is required along narrow stretches of verge, for example, where permanent loss of habitat results from communications ducting and creation of maintenance access footways along narrow stretches of verge. Locations of construction areas and other construction related activities are not yet known and detailed mitigation will be designed once this becomes available.
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Capture and relocation of great crested newts will be undertaken between March and October, depending on weather conditions. 8.6.67 An EPSL or PMW is likely to be required at the following chainage locations in line with the current survey results and design information (not including compounds, access routes and other construction activities where location is to be confirmed): Between chainage 37760 and chainage 38760 (anticlockwise carriageway); Between chainage 39600 and chainage 40500 (anticlockwise carriageway); Between chainage 42240 and chainage 43625 (clockwise carriageway); Between chainage 46200 and chainage 47300 (clockwise and anticlockwise carriageways); Between chainage 54600 and chainage 55700 (clockwise carriageway); Between chainage 58200 and chainage 59200 (clockwise and anticlockwise carriageways); and Between chainage 66200 and chainage Junction 27 (clockwise and anticlockwise carriageways). 8.6.68 Twenty-six ponds and ditches located within 500m of the scheme could not be accessed due to lack of permission. Further attempts will be made to secure access to survey the ponds prior to works commencing, to allow appropriate mitigation and licensing to be put in place if great crested newts are present. If this is not possible, it will be necessary to assume that great crested newts are present within the HA Boundary within this part of the scheme and undertake appropriate mitigation and EPSL. 8.6.69 Where temporary habitat loss is required, upon scheme completion re-planting, creation of log piles, rubble piles and hibernacula will be undertaken ensuring areas are restored and where possible, enhanced. 8.6.70 In areas where permanent habitat loss is required, where possible a buffer strip of habitat will be maintained or returned upon scheme completion to ensure habitat links are maintained and fragmentation is avoided. In areas where the verge is narrow and vegetation removal for installation of communications ducting and maintenance access footways results in the removal of all vegetation along the verge, additional planting to maintain connectivity is likely to be required, particularly in areas where adjacent habitats are not available to provide connectivity. Reptiles 8.6.71 Reptiles were found at five of the twenty five survey sites. Grass snakes were found at three sites and common lizards at two sites. The surveys indicate the presence of low species diversity, low population numbers and a relatively low number of sites where reptiles were recorded over the scheme as a whole. Due to the mobility of grass snakes and the sampling method of survey used, a precautionary approach should apply to those areas of suitable habitat that were not included in the detailed field survey due to access or safety reasons, as shown in Figure 2.1 to 2.13 in Appendix D6, but are near to locations reptiles were recorded as present. 8.6.72 Prior to commencement of construction works, a mitigation statement or management plan will be produced, including site clearance using local translocation of reptiles, sensitive timings of works, habitat manipulation and management, hand search, and ecological watching brief, as appropriate. 8.6.73 Where temporary works are confined to relatively discrete areas it is considered appropriate to move any reptiles from the working areas (either by translocation or habitat manipulation under a precautionary method of working), locally to the areas of unaffected soft estate with suitable habitat. Translocation to a dedicated receptor site will only be necessary if large areas of verge habitat are affected where there is no available adjacent verge habitat to act as a receptor site. This approach may be applicable to areas where ducting is required along narrow stretches of verge for example where permanent loss of habitat results from communications ducting and
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creation of maintenance access footways. Locations of construction areas are not yet known and detailed mitigation will be designed once this becomes available. Capture and relocation of reptiles will be undertaken between April and October, with optimal months being April/May or September/October. 8.6.74 Where temporary habitat loss is required, upon scheme completion re-planting, creation of log piles, rubble piles and hibernacula will be undertaken ensuring areas are restored and where possible, enhanced. 8.6.75 In areas where permanent habitat loss is required, a buffer strip of habitat will be maintained or returned upon scheme completion to ensure habitat links are maintained and fragmentation is avoided. In areas where the verge is narrow and vegetation removal for installation of communications ducting and maintenance access footways results in the removal of all vegetation along the verge, additional planting to maintain connectivity is likely to be required, particularly in areas where adjacent habitats are not available to provide connectivity. 8.6.76 Reptile mitigation is likely to be required at the following locations in line with current design, survey results and habitat types (not including compounds, access routes and other construction activities where location is to be confirmed): Between chainage 46300 and chainage 47500 (anticlockwise carriageway); Between chainage 49800 and junction 25 (clockwise carriageway); Between chainage 52600 and 54100 chainage (anticlockwise carriageway); Between chainage 56930 and chainage 60420 (anticlockwise carriageways). Birds 8.6.77 Suitable breeding bird habitat such as woodland and scrub is present within the scheme area and directly adjacent to it. Patches of broadleaved and mixed plantation woodland, scrub and scattered trees will be lost as a result of the scheme, in order to site ERAs, gantries and cantilevers and for ducting and maintenance access footways. Any vegetation clearance of suitable breeding bird habitat will be undertaken outside of the bird breeding season wherever possible. The core breeding season for most birds can be taken to run from the beginning of March to the end of August, but breeding often occurs in February or September for some species. Work outside this period runs less risk of destroying active nests although care is needed at all times to avoid committing an offence since birds have been recorded nesting in every month of the year. 8.6.78 If vegetation clearance outside the breeding season is not possible, a detailed inspection for breeding birds will be carried out no more than 24 hours prior to any works being undertaken. This minimises opportunities for nest building between the survey and the start of works. Any nest in use or being built during this inspection will need to be left undamaged, with an appropriate buffer of surrounding vegetation, for the entire nesting period and alternative approaches to the works proposed. 8.6.79 Where temporary habitat loss is required, upon scheme completion re-planting will be undertaken ensuring areas are restored and where possible, enhanced. 8.6.80 In areas where permanent habitat loss is required, a buffer strip of habitat will be maintained or returned upon scheme completion to ensure habitat links are maintained and fragmentation is avoided. 8.6.81 Lighting can affect bird behaviour through the disruption of natural rhythms and areas where large amounts of additional flood lighting is required for night work would be expected to cause the most disturbance. Lighting during night time works will therefore be strictly controlled. Baffles will be used where necessary to reduce light spill from construction floodlights. 8.6.82 Noise will be strictly controlled and kept to a minimum. Where possible, high levels of noise will be avoided in areas where nesting birds in adjacent habitats are known to be present.
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Terrestrial Invertebrates 8.6.83 Sensitive design of floodlighting during construction and minimising the loss of terrestrial habitat will mitigate impacts on terrestrial invertebrates. 8.7 Magnitude of Impacts (Change) 8.7.1 Impacts have been assessed against the criteria set out in IAN 130/10 Ecology and Nature Conservation: Criteria for Impact Assessment (Highways Agency, 2010). Impacts are described below and characterised in Tables 8.7 and 8.8. All statutory sites within the 2km search area and all non-statutory sites immediately adjacent to the scheme are included as well as habitats and species known or potentially present within the scheme area. Mitigation, enhancement and compensation measures used to avoid or minimise potential adverse effects have been taken into account. 8.7.2 This assessment has assumed that there will be a permanent loss of a 3m swathe of verge habitat immediately adjacent to the carriageway to allow for the installation of communications ducting and maintenance access footways. In addition to this there will be permanent loss of habitat for ERAs. Evaluations of significance of effects below assume that the above mitigation measures will be implemented. 8.7.3 Very approximately, between Junctions 23 and 27, the area of soft estate is 75 Ha. The permanent habitat loss as a result of the twelve ERAs proposed is approximately 0.36 Ha which equates to a loss of approximately 0.48% of the total soft estate between Junctions 23 and 27. Habitat loss for the gantries, cantilever signs, modification of existing gantries and post mounted signs are unknown at this stage, but the loss for these structures is likely to be within the 3m swathe to be cleared for communications ducting and installation of maintenance access footways on either side of the carriageway, which along the 25.78km length of the scheme approximately equates to 7.73 Ha (or 10.3% of the total soft estate). In addition to this there will be permanent habitat loss associated with widening at Junctions 23, 26 and 27 and around Bell Common Tunnel and Ivy Chimneys Underbridge (permanent footprint unknown). 8.7.4 This estimate does not include construction working areas associated with installation of ERAs, gantry legs, cabinets and other construction related activities, which are currently unknown and will result in temporary habitat loss. Habitats temporarily affected by construction working areas during the construction phase will be returned to verge habitat after scheme completion. 8.7.5 Locations of construction compounds, access tracks, storage areas and other construction related activities are not yet known and therefore cannot be fully assessed at this stage. Further assessment and development of detailed mitigation measures for these will need to be carried out once these are known and as the detailed design progresses. 8.7.6 In places the new infrastructure would take up the all of the soft estate particularly where the verge is very narrow. This would have an effect of severing habitat links which potentially result in fragmentation and reduction of the ecological function and diversity of the soft estate as a whole. 8.7.7 Habitats identified by the Phase 1 Habitat Survey are already subject to effects associated with the existing M25. However, with the loss of some areas of buffering habitat directly adjacent to the HA boundary as a result of the scheme, retained habitats currently situated behind the buffering habitat would be more exposed to the deposition of hydrocarbons, de-icing salt, particulates, and the effects of wind-throw. 8.7.8 The scheme is lit throughout and no new lighting is anticipated for the main line. It is currently expected that the ERAs are unlit but if the ERAs are to be lit, then this will be by short 7m high fully cut off lanterns using LED technology providing negligible increase to the existing operational lighting levels.
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Statutory Designated Sites 8.7.9 In accordance with DMRB Volume 11, Section 4 an Assessment of Impacts on European Sites (AIES) has been carried out to determine the significance of any impacts on these NATURA 2000 sites as a result of the scheme. The AIES is provided as an appendix to this report, which concludes that no significant effects are considered likely (subject to formal consultation with Natural England). Construction Phase Impacts 8.7.10 There will be no direct potential negative impacts on international or national statutory designated sites within the study area. 8.7.11 There is the potential for pollution of designated watercourses which link to the scheme, but these will be mitigated through strict pollution control measures outlined in the CEMP. These include: Lee Valley SPA and RAMSAR site (International value), which includes Thurnford and Cheshunt Pits SSSI; Cornmills Stream and Old River Lea SSSI (national value); and Chingford Reservoirs SSSI (national value). 8.7.12 No direct or indirect negative impacts are anticipated on Waltham Abbey SSSI (national value). 8.7.13 No direct or indirect impacts are anticipated to Curtismill Green SSSI (5.2km from scheme) and Water End Swallow Holes SSSI (3.5km from scheme). Both SSSIs are beyond J 27 which is outside the ecological study area. These SSSIs were only considered as potential receptors in the air quality assessment Chapter 5 as the AQ assessment needs to consider relevant receptors closest to the Affected Road Network (ARN) that include statutory designated sites sensitive to local air pollution. 8.7.14 Epping Forest SAC/SSSI is located adjacent to the HA Boundary and is of European value. 8.7.15 The SAC‟s habitats (Acidophilous Beech forest and North Atlantic Wet Heath) are qualifying features. Changes in air quality as a result of the scheme that could affect the habitats of the SAC are predicted to be negligible. The detailed results can be found in chapter 5 and in Appendix A. 8.7.16 Natural England outlined concerns regarding air quality impacts on Epping Forest SAC during the operational phase and during the construction phase, in particular the possibility that congestion resulting from widening works in the vicinity of Epping Forest may result in a significant increase in traffic using roads through the SAC. 8.7.17 Traffic management measures employed during construction are to retain 3 lanes running as demonstrated during the Bell Common Tunnel Refurbishment Scheme should reduce any rat running. Further, this will be monitored during construction. Traffic management arrangements for ALR are very different to those considered in the previous schemes, with less construction in ALR and thus less residence time in any one section of the scheme (at present it is estimated that works between chainages 50400-63100 will take approximately 39 weeks), but the actual time spent along the Bell Common areas are likely to be significantly less than that therefore reducing the likelihood of rat running through the forest. More details on mitigation measures to reduce air quality impacts are outlined in the chapter 5 (Air quality). 8.7.18 In accordance with DMRB Volume 11, Section 4 an Assessment of Impacts on European Sites (AIES) has been carried out to determine the significance of any impacts on these NATURA 2000 sites as a result of the Project. The AIES is provided as a separate report in Appendix A which concludes that no significant effects are considered likely (subject to formal consultation with Natural England). 8.7.19 Additionally, the potential exists for the following indirect impacts during the construction phase: Increased dust and construction related particulates; Accidental incursion by the workforce into adjacent sites;
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Disturbance to associated species (including badger, bats, otter, water vole, birds, great crested newt, reptiles, invertebrates (including stag beetle)) through noise, vibration, lighting; and Pollution from fuel spills and other such incidents. 8.7.20 With strict adherence to the CEMP, measures within the CEMP (described above) would minimise dust and pollution impacts. Disturbance to species associated with the designated site through noise and vibration, would be temporary and any animals present are likely to be habituated to the high levels of noise and vibration associated with the existing traffic. Impacts of temporary construction lighting will be minimised where possible by sensitive design. Fencing will be used to prevent accidental incursion by the workforce, where required. 8.7.21 Overall, the construction phase impacts of the scheme on statutory designated sites are considered to be slight adverse and not significant. Operational Phase Impacts 8.7.22 There would be no direct operational phase impacts on any statutory designated sites. 8.7.23 There is potential for indirect operational phase impacts on Epping Forest SAC/SSSI, which is directly adjacent to the scheme including: Increased deposition of hydrocarbons, de-icing salt and particulates; Disturbance to associated species (including badger, bats, otter, water vole, birds, great crested newt, reptiles, invertebrates (including stag beetle)) due to the closer proximity of traffic to the sites; and Pollution from fuel spills and other such incidents. 8.7.24 As a result of the scheme, traffic would be in closer proximity to Epping Forest SAC and its associated species. Effects to such species could include increased disturbance through noise and vibration. New low noise surfacing to the hard shoulder is proposed with replacement of the main running lanes surface with a low noise surface taking place only when the maintaining authority (DBFO MAC) have programmed resurfacing works. Generally, there would be negligible changes in noise levels associated with the scheme. Furthermore, any animals present are likely to be habituated to the high levels of noise, vibration and lighting associated with the existing traffic. Impacts of noise on birds are discussed below 8.7.25 For Chingford Reservoirs SSSI, downstream , there is the potential for pollution of watercourses from fuel spills or other incidents during operation but the risk of these is not significantly greater than at present and these will be mitigated through strict pollution control measures. 8.7.26 Detailed assessments of the change in air quality for designated sites are provided in Chapter 5 Air Quality. 8.7.27 This included an assessment of air quality impacts on Epping Forest SAC/SSSI within 200m of the scheme itself and two additional designated sites (Curtismill Green SSSI and Water End Swallow holes SSSI) within 200m of the road network where air quality may be affected by the change in traffic as a result of the scheme. Impacts of air quality on the Lea Valley SPA (International Value) were not considered likely due to the distance from the scheme (1.1km) and the associated road network. 8.7.28 For the designated sites included in the assessment, the estimated annual mean concentrations
of NOx were compared to the critical level. The estimated annual mean NO2 concentrations were used to determine annual rates of N deposition for comparison with critical loads. Estimates were made with the scheme in place („do something scenario‟ or DS) and without the Scheme („do minimum scenario‟ or DM) and also compared to the 2008 base year. Results have been derived in accordance with DMRB Volume 11, Part 1, Section 3, HA207/07 Annex F.
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8.7.29 Epping Forest SAC and Site of Special Scientific Interest (SSSI) is the only statutory designated site that is located directly adjacent to the scheme between junctions 26 and 27 around Bell Common Tunnel. A section of Epping Forest SAC also lies adjacent to the M11. For the purpose of the air quality assessment Epping Forest SAC has been determined as comprising two ecosystem types which are adjacent to the M25 Atlantic acidophilous beech forest and wet heath to the south of the M25 and the habitat in Epping Forest to the west of the M11 has been classified as broadleaved deciduous woodland. Potential impacts of exceeding N depositions critical load on beech forest habitats include: Changes in ground vegetation and mycorrhiza, nutrient imbalance, changes soil fauna. Potential impacts of exceeding N depositions critical load on wet heath habitats include: Transitions from heather to grass dominance. Potential impacts of exceeding N depositions critical load on broad leaved deciduous woodland habitats include: Changes in soil processes, nutrient imbalance, ground vegetation and mycorrhiza, nutrient imbalance. The critical load for all three habitat types (beech forest, wet heath and broad leaved deciduous woodland) is between 10-20 kgN/ha/yr. 8.7.30 Curtismill Green SSSI has been classified as ecosystem type Low and medium altitude hay meadows (www.apis.gov.uk). Potential impacts of exceeding N depositions critical load on grassland habitats include: Increase in tall grasses which will decrease species diversity. The critical load for this habitat type is between 20-30 kgN/ha/yr . 8.7.31 Water End Swallow Holes SSSI is designated for its geological features and any effects in the change of N deposition will not affect the status of the SSSI and therefore this will not be discussed any further.
8.7.32 The Air Quality Designated Sites assessment indicates that concentrations of annual mean NOx at Epping Forest SAC, Epping Forest SSSI and Curtismill Green SSSI exceed the 30 µg/m3 Critical Level for the protection of vegetation in 2015 with and without the scheme
3 8.7.33 At Curtismill Green SSSI, the scheme would add a maximum of 0.5 µg/m of NOx to the total annual mean concentration at the transect receptor nearest the road. 8.7.34 At Epping Forest SAC the results presented in Appendix 5 Table A5.14 indicate that the scheme will result in estimated increases of more than 2 µg/m3, within approximately 150m of the road centreline. Estimated concentrations at Epping Forest transect 4 to the east of the designated site exceed the 30 µg/m3 Critical Level within 185 m of the M25. The scheme would increase 3 concentrations over the DM, but would only add a maximum of 1.4 µg/m of NOx to the total annual mean NOx concentration at the nearest transect receptor to the road centreline. 8.7.35 Overall, NOx concentrations presented in Chapter 5 of the EAR are predicted to decline in future years, with or without the scheme as compared with the base scenario.
8.7.36 Current methods used for predicting future local air quality concentrations of NO2 may result in an overly optimistic prediction of local air quality for assessments covering years 2011 to around
2020. This has been addressed in the „Technical Note – Projecting NO2: Gap Analysis on Long Term Trends (EAR Results)‟. The findings for transect receptors within the Epping Forest SAC are
that NOx concentrations are likely to be higher in both the DM and DS scenarios in the opening year, than the values presented in Chapter 5 of the EAR, however they still reflect an overall
downward trend in NOx concentrations when compared to the base year. The results indicate that the scheme will result in estimated increases of more than 2 µg/m3, within approximately 200m of the road centreline for transects 1, 2 and 3 and within approximately 120m for transect 4. The results of the air quality modelling for the opening year show that most (29 out of 37) of the habitat receptors found within 200m of the M25 are expected to exceed the Critical Level with an expected increase of 2ug/m3 or more as a result of the scheme.
8.7.37 The results of the evaluation of significance for designated ecological sites presented in Chapter 5
of the EAR and reassessment in the „Technical Note – Projecting NO2: Gap Analysis on Long Term Trends (EAR Results)‟ finds the overall conclusion on the M25 Section 5 scheme for the
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effect of annual average NOx on designated ecological sites is that there would be no overall significant effects.
8.7.38 For the Curtismill Green SSSI transect, deposition rates are predicted to be below the lower bound of the critical load of 20-30kgN/ha/yr in the DM and the DS in 2015. The background deposition rate at this site is 15.5kgN/ha/yr and the road increment at the transect receptor closest to the road is 6% of the overall deposition rate. The maximum increase in deposition rate as a result of the scheme is 0.1kgN/ha/yr. 8.7.39 Assessment of the changes in total N deposition as a result of the scheme indicate that deposition rates are higher than the Critical Loads for the sensitive features within the Epping Forest SAC and Epping Forest SSSI adjacent the M11, mostly attributed to the high background N deposition rates. The maximum increase in the road increment contribution to the total N deposition rates is 0.4 kgN/ha/yr compared to the DM, which is a change of 1%. 8.7.40 Although the scheme (DS) results in an increase in pollutants compared to the DM scenario, it is considered unlikely that these localised increases will result in significantly greater impacts on the habitats present. This is based on by the data presented in the air quality chapter. 8.7.41 Overall, the operational impacts of the scheme on designated sites are considered to be negligible and not significant. Non Statutory Designated Sites Construction Phase Impacts Direct Impacts 8.7.42 There are nine non-statutory designated sites located adjacent to the Highways Agency Boundary between junctions 23 and 27. These are of county value. Whilst there will be no direct negative impacts upon these sites, the potential exists for the following indirect impacts during the construction phase: Increased dust and construction related particulates; Accidental incursion by the workforce into adjacent sites; Disturbance to associated species (including badger, bats, otter, water vole, birds, great crested newt, reptiles, invertebrates and stag beetle) through noise, vibration, lighting; and Pollution from fuel spills and other such incidents. 8.7.43 With strict adherence to the CEMO, measures within the CEMP (described above) would minimise dust and pollution impacts. Disturbance to species associated with the designated site through noise and vibration, would be temporary and any animals present are likely to be habituated to the high levels of noise and vibration associated with the existing traffic. Impacts of temporary construction lighting will be minimised where possible by sensitive design. Fencing will be used to prevent accidental incursion by the workforce, where required. 8.7.44 Overall, the construction phase impacts of the scheme on non-statutory designated sites are considered to be negligible and not significant. Operational Phase Impacts 8.7.45 The potential exists for indirect impacts on adjacent statutory and non-statutory designated sites that are directly adjacent to the Project including: Increased deposition of hydrocarbons, de-icing salt and particulates; Disturbance to associated species (including badger, bats, otter, water vole, birds, great crested newt, reptiles, invertebrates (including stag beetle)) due to the closer proximity of traffic to the sites; and
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Pollution from fuel spills and other such incidents. 8.7.46 As a result of the scheme, traffic would be in closer proximity to the designated sites and their associated species. Effects to such species could include increased disturbance through noise and vibration. New low noise surfacing to the hard shoulder is proposed with replacement of the main running lanes surface with a low noise surface taking place only when the maintaining authority (DBFO MAC) have programmed resurfacing works. Generally, there would be negligible changes in noise levels associated with the scheme. Furthermore, any animals present are likely to be habituated to the high levels of noise, vibration and lighting associated with the existing traffic. Impacts of noise on birds are discussed below. 8.7.47 For non statutory designated sites downstream, there is the potential for pollution of watercourses from fuel spills or other incidents during operation but the risk of these is not significantly greater than at present but these will be mitigated through strict pollution control measures. 8.7.48 No detailed air quality assessment has been made for non statutory sites, but it would be expected that changes to pollutant levels on adjacent non statutory designated sites would be similar to those described for statutory designated sites above, with pollutant levels in general likely to be decreasing, but with slighty increased levels of pollutants expected with the scheme than without. It is considered unlikely that any localised increases will result in significantly greater impacts on the habitats present than those that would have occurred without the scheme. 8.7.49 Overall, the operational impacts of the scheme on non statutory designated sites are considered to be negligible and not significant. Habitats within the HA Boundary 8.7.50 Potential construction effects upon habitats within the Highways Agency boundary include: Permanent and temporary loss of habitats of value for foraging / sheltering / hibernating protected species (scrub, grassland, shrubs, trees) in discrete areas; Permanent and temporary fragmentation and loss of connectivity between habitats of value for foraging / sheltering / hibernating protected species (scrub, grassland, shrubs, trees) in discrete areas; Potential for indirect impacts associated with pollution from fuel spills and other such incidents; Edge effects on adjoining habitats including exposure to wind-throw due to the removal of shielding plantation woodland; Increased deposition of dust and construction related particulates; and Accidental incursion by the workforce into adjacent retained habitats. 8.7.51 Very approximately, it is estimated that about 8 ha of habitat will be lost as a result of ERAs and on the assumption that 3m of verge habitat either side of the carriageway will be permanently lost (not including further loss as a result of small strips to be lost for widening, the areas of which are currently unknown). 8.7.52 Construction working areas associated with installation of ERAs, gantry legs, cabinets and other construction related activities are also currently unknown and will result in temporary habitat loss. 8.7.53 Native broad-leaved woodland and aquatic habitats of local value are not affected. The habitats affected by the scheme are of negligible value. Provided mitigation outlined above is implemented, it is considered that overall, the construction phase impacts of the scheme on habitats inside the Highways Agency boundary are considered to be neutral and not significant. Operational Phase Impacts Permanent loss of habitats of value for foraging/sheltering/hibernating protected species (scrub, grassland, shrubs, trees) in discrete areas
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Permanent fragmentation and loss of connectivity between habitats of value for foraging/sheltering/hibernating species (scrub, grassland, shrubs, trees) in discrete areas; and Increased deposition of hydrocarbons, de-icing salt and particulates. 8.7.54 Outside of designated sites, which are discussed above, permanent loss relates to habitats of negligible value. Provided the mitigation described above is implemented, the potential impacts of fragmentation and loss of connectivity can be minimised sufficiently to conclude that overall, the operational impacts of the scheme on habitats inside the Highways Agency boundary are considered to be neutral and not significant. Habitats outside the HA Boundary Construction Phase Impacts 8.7.55 None of the habitats outside of the HA boundary would be directly affected through habitat loss as a result of the scheme. Those adjacent to the HA boundary may be subject to indirect impacts associated with traffic being in closer proximity to the habitat as a result of the use of the hard shoulder but the effects of this are considered to be minimal. 8.7.56 None of the culverts or watercourses within the Study Area will be modified by the proposals. The adoption of pollution prevention measures and best practice guidelines outlined in the proposed CEMP would ensure that all reasonable measures are undertaken to prevent adverse changes to the watercourses and ensure statutory compliance. 8.7.57 Potential construction effects upon habitats outside the HA boundary, particularly those directly adjacent to the scheme include: Increased dust and construction related particulates; Isolation of habitats caused by removal of connecting habitats within the HA boundary; Edge effects on adjoining habitats including exposure to wind-throw due to the removal of shielding plantation woodland; and Pollution from fuel spills and other such incidents. 8.7.58 As a result of the scheme, traffic would be in closer proximity to adjacent habitats, but there is sufficient retained buffering habitat resulting in the impacts being minimal. Provided they are adhered to, measures within the CEMP (described above) would minimise dust and pollution impacts. 8.7.59 Disturbance to species associated with adjacent habitats through noise and vibration would be temporary and any animals present are likely to be habituated to the high levels of noise and vibration associated with the existing traffic. Impacts of temporary construction lighting will be minimised where possible by sensitive design. 8.7.60 Fencing will be used to prevent accidental incursion by the workforce, where required. Overall, the construction phase impacts of the scheme on habitats outside the HA boundary are considered to be neutral and not significant. Operational Phase Impacts 8.7.61 Operational effects relating to the scheme are not envisaged to be different from the current situation along the majority of the route. Areas of habitat within the HA boundary will have been reduced, which would have a knock-on effect in terms of a reduction in buffering habitat to the habitats outside of the HA boundary, but this is not predicted to result in changes to the habitat outside of the HA boundary. Impacts are considered to be neutral and not significant. Protected and Notable Species 8.7.62 An assessment of the construction and operational impacts on protected and notable species that have been recorded or have the potential to be present within the scheme area is presented
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below. For species, construction and operational phase impacts are considered together. Mitigation has been included for deer due to the human health and safety issues resulting from collision risks. However, they are not considered a receptor in ecological EIA terms and are therefore not included in this assessment section. In the same way, mitigation measures are set out for preventing the spread of invasive species of plant, but they are not themselves a receptor. Notable Plants 8.7.63 An area of the nationally scarce yellow vetchling would be lost during the construction phase. This is of local value. Following construction, native grassland and wildflower species mix with locally sourced yellow vetchling included to be sown and areas adjacent will be seeded to compensate for areas of permanent loss. The impact on yellow vetchling is considered to be neutral and not significant. Mammals Badgers 8.7.64 No loss of known badger setts is predicted. The potential construction phase impacts on badgers include: Disturbance to existing and previously unknown setts; Loss of foraging habitat; Injury as a result of falling into steep-sided excavations; and Temporary blockage of traditional commuting and foraging routes. 8.7.65 Steep sided excavations would present a trapping or injury hazard and should therefore contain a means of escape and be covered at night, as detailed above. There will be a loss of narrow strips of foraging habitat, but suitable adjacent habitat will be retained. 8.7.66 Overall, the construction phase impacts of the scheme are considered to be neutral and not significant on badgers, which are considered of negligible value. 8.7.67 Potential effects on badgers during the operation of the scheme include: 8.7.68 Increased disturbance through noise and vibration due to loss of buffering habitat and therefore current setts and foraging grounds being in closer proximity to the M25. 8.7.69 During the operational phase, traffic will be slightly closer to setts than currently. However, any badgers using this area are already adjacent to the existing M25 and therefore, would already be expected to be habituated to levels of noise and vibration associated with the existing motorway. The impact is therefore considered to be neutral and not significant. Dormice 8.7.70 It is theoretically possible that dormice may be present, in woodland and scrub habitats within the HA boundary, but remain undetected by surveys, particularly where these habitats link to woodland. 8.7.71 Potential construction phase impacts on dormice include a low risk of: Incidental injury or mortality; Loss of and fragmentation of foraging habitat; and Loss of place of shelter/hibernation. 8.7.72 To avoid potential incidental injury or mortality to individual dormice, advanced mitigation works (as outlined above) would be implemented. 8.7.73 Areas of potential dormouse habitat (mainly woodland and scrub) will be permanently lost at the location of some proposed ERAs, gantries, signsand as a result of ducting and maintenance access footways. Further habitat loss will be temporary where vegetation clearance for working
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areas is necessary. These temporary and permanent losses of discrete areas of habitat are unlikely to significantly affect dormouse populations, should they be present in the local area, due to the proposed mitigation which aims to reduce the areas of potential dormouse habitat lost and avoid fragmentation of dormouse habitat. 8.7.74 Overall, provided the mitigation proposed is implemented, the construction phase impacts of the scheme on dormice are considered to be neutral and not significant. 8.7.75 Potential operational effects on dormice include: Increased noise disturbance due to closer proximity of traffic to potential dormouse habitat. 8.7.76 Where permanent loss of habitat is required, buffer strips of habitat will be retained where possible, maintaining the connectivity of the remaining habitats. In addition, compensatory planting will help to improve the habitat suitability for dormice during the operation of the scheme. 8.7.77 Overall, the operational impacts of the scheme on dormice are considered to be neutral and not significant. Bats 8.7.78 Potential construction phase impacts on bats include: Reduction of foraging habitat; Disturbance resulting from night working (flashing lights, floodlighting, noise, workmen, machines); and Reduction in habitat connectivity through creation of gaps in scrub and/or woodland cover. 8.7.79 Once all construction arrangements are known, trees assessed as having potential to support bats will be assessed for possible impacts. Where necessary appropriate mitigation and EPSL will be implemented. 8.7.80 Only a small proportion of the available foraging and commuting habitat will be lost as a result of the scheme, and fragmentation of potential flight lines will be avoided as far as possible. Therefore, the impact upon foraging habitat and commuting routes will be minimal. Replacement planting will be incorporated wherever possible to link up fragmented habitats. 8.7.81 Floodlighting (and possibly other forms of construction related lighting) has been shown to affect bat foraging behaviour and the use of roosts. In the unlikely event that a roost is confirmed, direct illumination by lighting would be avoided, as this could cause disruption to bat emergence times and/or cause bats to abandon the roost. 8.7.82 Overall, the construction phase impacts of the scheme on bats, which are considered of local value, are anticipated to be neutral and not significant. 8.7.83 During operation, there is the potential for increased mortality of bats due to closer proximity of traffic to commuting/ foraging habitat, but the risk of this is considered minimal and where permanent habitat loss occurs, buffer strips will be retained to ensure connectivity where possible. The operational impacts of the scheme on bats are considered to be neutral and not significant.
Otter and water vole 8.7.84 The presence of water voles and otters was confirmed within the scheme area on various watercourses along the scheme. Otters and water voles are considered to be of local value. 8.7.85 None of the culverts or watercourses within the Study Area will be modified by the proposals. Potential construction phase impacts on water vole and otter include: Degradation of habitat through changes in water quality (e.g. through poor storage of contaminants or fuel);
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Input of silt-laden run-off caused by vegetation clearance, ground disturbance and earth moving within the impact zone; and Disturbance resulting from night working, additional lighting. 8.7.86 The adoption of pollution prevention measures and best practice guidelines outlined in the proposed CEMP would ensure that all reasonable measures are undertaken to prevent adverse changes to the watercourses and ensure statutory compliance. 8.7.87 Disturbance to migrating otters could occur where Hobbs Cross stream passes under the M25 and where potential otter signs have been recorded. Mitigation to minimise any disturbance to migrating otters travelling through the area will include the avoidance of night-time works in proximity to the stream or careful control of construction lighting will be required if night time working cannot be avoided. 8.7.88 Overall, the construction phase impacts of the scheme on water voles and otters are considered to be neutral and not significant. 8.7.89 In the operational phase, the risk of increased pollution from accidental spillages would remain within acceptable limits. Overall, the operational phase impacts of the scheme on otters are considered to be neutral and not significant. Herptiles Great Crested Newt 8.7.90 Surveys have revealed presence of great crested newts in ponds within 500m of the scheme. Low to medium population sizes were recorded in 2010 and these are considered of local value. No ponds are to be directly lost through the scheme, but terrestrial habitat (primarily grassland, scrub and woodland) on the motorway verge which links to some of the ponds, will be lost and could be habitat used by great crested newts. This temporary and permanent loss of habitat linked to the scheme is unlikely to affect great crested newt populations in the local area due to the populations sizes recorded, presence of alternative habitat, and extent and location of proposed ground works. 8.7.91 Potential construction phase impacts on great crested newts include: Incidental injury or mortality; Loss, reduction or degradation of terrestrial habitat; and Loss of places of shelter/hibernation. 8.7.92 To avoid incidental injury or mortality to individual newts, advanced mitigation works (as stated above) would be implemented. 8.7.93 To compensate for loss of places or shelter/ hibernation, adjoining habitats will be enhanced with suitable structures rubble piles, log piles and hibernacula. Vegetation clearance will be minimised as far as possible and buffer strips maintained around structures to avoid the fragmentation of terrestrial habitats where possible. Replacement planting will be incorporated wherever possible to link up fragmented habitats. 8.7.94 Overall, the construction phase impacts of the scheme on great crested newts are considered to be slight adverse and not significant. 8.7.95 Potential operational effects on great crested newts include: Mortality associated with the mowing of grass verges or mechanical litter picking adjacent to the M25; and Severance / fragmentation of habitats and loss of connectivity linked to the structures (ERA‟s etc).
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8.7.96 Should great crested newts utilise the highway verge for foraging and/or hibernation, effects associated with mowing and mechanical litter picking would continue at a similar magnitude to the existing situation. However, such effects are not likely to differ from the existing situation and proposals for sensitive management during the operational phase will be incorporated into the Handover Environmental Management Plan. 8.7.97 Where permanent loss of habitat is required, buffer strips of habitat will be retained maintaining the connectivity of the remaining habitats. In addition, measures outlined above, such as the provision of log piles and hibernacula, would help to improve the habitat suitability for reptiles during the operation of the scheme. 8.7.98 Overall, the operational impacts of the scheme on great crested newts are considered to be neutral and not significant. Reptiles 8.7.99 Areas of suitable reptile habitat will be lost in order to site ERAs, gantriesand cantilevers. Potential construction phase impacts on the local reptile populations include: Incidental, injury or mortality; Reduction, loss or degradation of habitat; Loss of places of shelter/hibernation; and Displacement of individuals into sub-optimal habitat. 8.7.100 Loss of habitat for shelter and foraging would occur with removal of grassland and scrub habitat. This may lead to individuals being displaced into sub-optimal habitat and therefore subject to increased exposure and predation risks. To compensate for loss of places of shelter/hibernation, adjoining habitats will be enhanced with suitable structures rubble piles, log piles and hibernacula. Vegetation clearance will be minimised as far as possible and buffer strips maintained around structures to avoid the fragmentation of terrestrial habitats. Replacement planting will be incorporated wherever possible to link up fragmented habitats. 8.7.101 Overall, the construction phase impacts of the scheme on reptiles are considered to be neutral and not significant. 8.7.102 Potential operational effects on reptiles include: Mortality associated with mowing and mechanical litter picking on the grass verge; Potential habitat fragmentation caused by isolation of potential basking habitat. 8.7.103 Mortality associated with grass mowing is likely to continue at current rates but is largely unavoidable and likely to be of a similar magnitude to the existing situation. In addition, measures outlined above, such as the provision of log piles and hibernacula, would help to improve the habitat suitability for reptiles during the operation of the scheme. Measures to mitigate habitat fragmentation have been outlined above. 8.7.104 Overall, the operational impacts of the scheme on reptiles are considered to be neutral and not significant. Birds 8.7.105 Potential breeding habitat for birds that needs to be removed as part of construction would be carried out during winter months, wherever possible. Therefore, direct effects on breeding birds would be minimal. Potential construction phase impacts on birds include: Small reduction in suitable breeding, shelter and feeding habitats; Disturbance or destruction of active nests; and Disturbance (lighting, noise, machinery, visual presence of humans).
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8.7.106 Removal of small amounts of woodland and scrub would reduce the amount of habitat suitable for shelter, foraging and nesting and may lead to increased mortality through exposure or predation. However, similar and more suitable habitat exists nearby. 8.7.107 Lighting can affect bird behaviour through the disruption of natural rhythms and areas where a large amount of additional flood lighting is required for night work would be expected to cause the most disturbance. This may result in reduced breeding success for any birds nesting close to the construction area. This would be a temporary negative impact. 8.7.108 Visual disturbance from the construction workforce, as well as the increased movement of machinery, noise and vibration may have a temporary negative effect on any birds breeding close to the construction area (e.g. reduced breeding success). However, birds in this area are already located adjacent to the existing M25 and would be expected to be habituated to the existing levels of disturbance from the operational motorway. 8.7.109 Overall, the construction phase impacts of the scheme are considered to be neutral and not significant on breeding birds, which are of negligible value. 8.7.110 Potential operational effects on birds include: Traffic generated disturbance, particularly through noise which may affect breeding success Disturbance during routine management operations Possible increased mortality due to closer proximity of traffic to breeding/ foraging habitat 8.7.111 The increased proximity of traffic to habitats within the scheme as well as adjacent habitats would lead to localised changes in noise levels. However, new low noise surfacing to the hard shoulder is anticipated. 8.7.112 Overall, the operational impacts of the scheme on breeding birds are considered to be neutral and not significant. Terrestrial Invertebrates 8.7.113 Potential construction impacts on terrestrial invertebrates include: Direct permanent and temporary disturbance and loss of terrestrial habitat; and Increased mortality of nocturnal insects due to increased temporary lighting 8.7.114 Moths and other night-flying insects are attracted to lights, and flood lighting may adversely affect their populations, causing disorientation and increasing susceptibility to predation. Lighting has also been shown to cause invertebrates to move closer to the surface, thus increasing their risk of predation. Diurnal predators may also forage for longer in artificially lit environments. However, any flood lighting would be directional to minimise on adjacent habitats, and would only be temporary in nature. Overall, the construction phase impacts of the scheme are considered to be neutral and not significant on terrestrial invertebrates, which are of negligible value. 8.7.115 Habitats will be permanently lost, but the loss is minimal and retained habitats will be enhanced. As it is expected that the habitats present will contain assemblages of common species, it is considered that the operational phase impacts on terrestrial invertebrates will be neutral and not significant.
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Table 8.2 - Summary of Construction Impacts, Mitigation and Significance Resource Value Summary of Potential Impacts Characterisation Summary of Mitigation Significance of of Impacts impacts after mitigation Lee Valley SPA and RAMSAR International Pollution of watercourses which link Negative, unlikely Implementation of strict pollution Neutral Site, which includes Turnford and National to this site. (provided pollution prevention measures through the Not significant and Cheshunt Pits SSSI; control measures CEMP Cornmills Stream and Old River are implemented Lea SSSI; Chingford Reservoirs through the SSSI CEMP), Indirect, Reversible, Temporary Epping Forest SAC and SSSI European Potential congestion resulting from Negative, possible, Structures located away from Slight Adverse widening works in the vicinity may temporary, receptor; Implementation of dust, Not significant result in a significant increase in reversible, indirect, noise and light and aquatic pollution traffic using roads through the SAC; control measures through the Increased dust and construction CEMP; related particulates; Fencing to prevent to prevent Accidental incursion by the accidental incursion of workforce; workforce into adjacent sites; Traffic management measures Disturbance to associated protected during construction to minimise use species; of local roads through the SAC. Pollution from fuel spills and other such incidents. Waltham Abbey SSSI National None anticipated N/A N/A Neutral Not significant Non statutory designated sites County Increased dust and construction Negative, Structures located away from Negligible adjacent to the HA boundary related particulates; probable, receptors, where possible and Not significant Accidental incursion by the temporary, vegetation clearance minimised on workforce into adjacent sites; reversible, indirect, adjacent verges; Disturbance to associated protected Buffer habitat retained between species; works and designated site, wherever possible; Pollution from fuel spills and other such incidents Implementation of dust, noise and light control measures and strict pollution control measures through
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Resource Value Summary of Potential Impacts Characterisation Summary of Mitigation Significance of of Impacts impacts after mitigation the CEMP; Fencing to prevent to prevent accidental incursion of workforce Implementation of dust, noise and light control measures through the CEMP. Habitats within the HA boundary Negligible Approximately 8 Ha of permanent Negative, certain, Working methods ensure site Neutral and local habitat loss, approximately equates direct, reversible, clearance is kept to a minimum; Not significant to a loss of approximately 10% of temporary Sensitive habitats of local value are the total soft estate between avoided (impacts only anticipated to Junctions 23 and 27. negligible value habitats); Fragmentation of habitats where Encroachment into adjacent verge is narrow; habitats will be prevented with fencing; Edge effects on adjoining habitats including exposure to wind-throw; Implementation of dust, noise and light control measures and strict Increased dust and construction pollution control measures through related particulates; the CEMP; Pollution from fuel spills and other Buffer habitats retained wherever such incidents; possible; Accidental incursion by the Restoration of habitats following workforce into adjacent retained construction; habitats. Planting to maintain habitat connectivity; Enhancement of retained verge habitats. Habitats outside the HA Negligible Increased dust and construction Negative, Implementation of dust, noise and Neutral boundary related particulates; probable, light control measures and strict Not significant Fragmentation of habitats; temporary, pollution control measures through reversible, indirect, the CEMP; Pollution from fuel spills and other such incidents; Buffer habitats retained between works and adjacent habitats, Edge effects on adjoining habitats wherever possible; including exposure to wind-throw
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Resource Value Summary of Potential Impacts Characterisation Summary of Mitigation Significance of of Impacts impacts after mitigation due to the removal of shielding Encroachment into adjacent plantation woodland. habitats will be prevented with fencing.
Yellow vetchling Local Loss of habitat where this species is Negative, Fencing of construction area to Neutral present and individual plants. probable, direct, prevent encroachment into retained Not significant reversible, habitat; temporary Following construction, native grassland and wildflower species mix with locally sourced yellow vetchling included to be sown; Adjacent areas to be seeded to compensate for areas of permanent loss. Badgers using the HA soft Negligible Disturbance to existing setts and Negative, Pre-construction survey to confirm Neutral estate previously unknown setts; probable, indirect, status of known setts and to locate Not significant Injury as a result of falling into reversible, any new entrances/setts; excavations; temporary Fencing to avoid inadvertent Temporary blockage of traditional disturbance of sett within 30m; commuting and foraging routes; Steep sided excavations to contain Loss of foraging habitat; a means of escape; Loss of narrow strip of foraging Disturbance licence for badgers if habitat. required.
Bats using the HA soft estate Local Reduction in foraging habitat; Negative, certain, Pre-construction survey if any trees Neutral Disturbance from night working; direct, reversible, to be affected; Not significant temporary Reduction in habitat connectivity. Retention of buffer habitat to maintain flight lines where possible; Clearance of vegetation to be kept to a minimum; Reinstatement of foraging habitat temporarily lost during construction;
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Resource Value Summary of Potential Impacts Characterisation Summary of Mitigation Significance of of Impacts impacts after mitigation Appropriate timings of works in sensitive areas; Strict control of lighting through measures in the CEMP. Dormice using the HA soft Negligible, Risk of killing, injury or Negative, unlikely, Precautionary method of working Neutral, not significant estate but subject to disturbance of individual dormice; indirect, reversible, required; legal permanent. Destruction of potential dormouse Mitigation in accordance with best protection if practice; and present habitat resulting in reduced Avoidance of habitat loss and foraging and shelter opportunities; fragmentation as far as possible. Fragmentation of potential dormouse habitat; Otters and water voles using Local Degradation of habitat through Negative, unlikely, Proposals do not involve any Neutral watercourses crossing the changes in water quality (quality indirect, reversible, modification of culverts, Not significant scheme (e.g. through poor storage of temporary watercourses or waterbodies or outfalls; contaminants or fuel); Avoidance of night-time works near Input of silt-laden run-off caused Hobbs Cross Stream; by vegetation clearance, ground Pre-construction surveys at disturbance and earth moving watercourses, which are most likely within the impact zone; to support; Disturbance resulting from night Pre-construction surveys for water working, additional lighting. voles on Mimmshall Brook; Strict pollution control measures
through the CEMP. Great crested newts using the Local Incidental injury or mortality; Negative, certain, Mitigation to translocate animals Slight adverse HA soft estate Loss, reduction or degradation of direct, reversible, (under licence) from areas where Not significant terrestrial habitat; temporary an offence is likely; Loss of places of Upon scheme completion shelter/hibernation. temporary areas to be re-planted and habitat piles created; Buffer strips of habitat maintained or returned on scheme completion; Document No: 5084755-S5-DO-EN-251 Page 164
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Resource Value Summary of Potential Impacts Characterisation Summary of Mitigation Significance of of Impacts impacts after mitigation Enhancement of retained habitat areas using re-planting and creation of log piles, rubble piles and hibernacula. Reptiles using the HA soft estate Local Incidental injury or mortality; Negative, certain, Translocation/habitat manipulation Neutral Loss, reduction or degradation of direct, reversible, to exclude animals from areas Not significant terrestrial habitat; temporary where an offence is likely; Loss of places of Upon scheme completion shelter/hibernation; temporary areas to be re-planted and habitat piles created; Displacement of individuals into sub-optimal habitat. Buffer strips of habitat maintained or returned on scheme completion; Enhancement of retained habitat areas using re-planting and creation of log piles, rubble piles and hibernacula. Birds using the soft estate Negligible Small reduction in suitable Negative, certain, Clearance of vegetation will be kept Neutral breeding, shelter and feeding indirect, reversible, to a minimum; Not significant habitats; temporary Clearance of vegetation will be carried out outside of the bird Disturbance or destruction of breeding season, where possible active nests; (and if not possible, ecologist will do Disturbance (lighting, noise, pre-clearance check for nests); machinery, visual presence of Replanting of lost vegetation; humans). Retention of habitat buffer strips; Use of baffles and strict control of lighting during night-time works; Strict control of noise and disturbance Terrestrial Invertebrates using Negligible Direct temporary disturbance and Negative, Habitat loss will be kept to a Neutral the soft estate loss of terrestrial habitat; probable, direct, minimum; Not significant reversible, Increased mortality of nocturnal Sensitive design and control of temporary lighting during construction
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Resource Value Summary of Potential Impacts Characterisation Summary of Mitigation Significance of of Impacts impacts after mitigation insects due to increased temporary lighting.
Table 8.3 - Summary of Operational Phase Impacts, Mitigation and Significance Resource Value Summary of Potential Impacts Characterisation of Summary of Significance Impacts Mitigation Lee Valley SPA and RAMSAR Site, International and Pollution of watercourses which link Negative, unlikely, Implementation of Neutral which includes Turnford and National to this site. Indirect, Reversible, strict pollution Not significant Cheshunt Pits SSSI; Cornmills Temporary. prevention Stream and Old River Lea SSSI; measures. Chingford Reservoirs SSSI Epping Forest SAC and SSSI and European Increased deposition of Negative, probable, No habitat loss Negligible adjacent non-statutory sites hydrocarbons, de-icing salt and temporary, reversible, outside of HA Not significant particulates; indirect. boundary; Disturbance to associated species; Design incorporates Pollution from fuel spills and other buffer habitat such incidents. between structures and adjacent habitats within protected sites. Waltham Abbey SSSI National None anticipated N/A N/A Neutral Not significant Yellow vetchling Local None anticipated N/A N/A Neutral Not significant Habitats within the HA boundary Local and Increased deposition of Negative, certain, Habitats temporarily Neutral Negligible hydrocarbons, de-icing salt and direct, not reversible, affected during Not significant particulates, permanent construction will be restored following Document No: 5084755-S5-DO-EN-251 Page 166
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Resource Value Summary of Potential Impacts Characterisation of Summary of Significance Impacts Mitigation works. Habitats outside the HA boundary Negligible Not anticipated to be different to the Negative, probable, None proposed Neutral current situation temporary, reversible, Not significant indirect, Badgers using the HA soft estate Negligible Increased disturbance through Negative, unlikely, No additional Neutral noise and vibration due to loss of indirect, not reversible, mitigation proposed Not significant buffering habitat and therefore setts permanent are closer to carriageway Bats using the HA soft estate Local Increased mortality due to closer Negative, unlikely, Where permanent Neutral proximity of commuting/foraging indirect, not reversible, loss habitat buffer Not significant habitat to motorway permanent strips to be created to ensure connectivity is still in place. Dormice using the HA soft estate Negligible, but Increased noise and disturbance Negative, unlikely, Where permanent Neutral subject to legal due to closer proximity to traffic indirect, not reversible, loss habitat buffer Not significant protection if permanent. strips to be created present to ensure connectivity is still in place. Otters and water voles using Local No additional impacts are N/A No additional Neutral watercourses crossing the scheme anticipated during the operational mitigation proposed Not significant phase Great crested newts using the HA Local Mortality associated with Negative, unlikely, Habitat loss kept to a Neutral soft estate maintenance operations; direct, non reversible, minimum through Not significant Severance/fragmentation of permanent design habitats Where permanent loss habitat buffer strips to be created to ensure connectivity is still in place; Adjoining unaffected habitats to be
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Resource Value Summary of Potential Impacts Characterisation of Summary of Significance Impacts Mitigation enhanced through log piles, rubble piles and hibernacula creation; Areas temporarily affected during construction will be restored on completion of works Reptiles using the HA soft estate Local Mortality associated with Negative, unlikely, Habitat loss kept to a Neutral maintenance operations; direct, non reversible, minimum through Not significant Severance/fragmentation of permanent design; habitats; Where permanent loss habitat buffer strips to be created to ensure connectivity is still in place; Adjoining unaffected habitats to be enhanced through log piles, rubble piles and hibernacula creation; Areas temporarily affected during construction will be restored on completion of works. Birds using the soft estate Negligible Traffic generated disturbance, Negative, unlikely, Impacts considered Neutral particularly through noise; indirect, not reversible, to be similar to the Not significant permanent current situation, Disturbance during routine therefore no management operations; additional mitigation Possible increased mortality due to proposed. closer proximity of traffic to Document No: 5084755-S5-DO-EN-251 Page 168
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Resource Value Summary of Potential Impacts Characterisation of Summary of Significance Impacts Mitigation breeding/ foraging habitat
Terrestrial Invertebrates using the Negligible Mortality associated with Negative, certain, Where permanent Neutral soft estate maintenance operations; direct, not reversible, loss habitat buffer Not significant Severance/fragmentation of permanent strips to be created habitats to ensure connectivity is still in place; Adjoining unaffected habitats to be enhanced through log piles, rubble piles and hibernacula creation, re- seeding/replanting; Areas temporarily affected during construction will be restored on completion of works
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8.8 Significant Effects 8.8.1 All of the impacts have been assessed as either neutral or slight adverse and are not considered significant. 8.9 Indication of Any Difficulties Encountered 8.9.1 No serious difficulties have been encountered when undertaking this assessment although some surveys were restricted by access constraints (health and safety and landowners refusing access) to both the soft estate and private land. 8.9.2 The full extent of all construction working areas is not yet known; therefore further development of detailed mitigation measures will be required during the detailed design phase, once these are confirmed. 8.10 Summary 8.10.1 There would be no long term impacts on designated sites although there would be a risk of a slight adverse effect during construction on Epping Forest SAC/SSSI but this is not considered significant. 8.10.2 Any risk of potential impacts on designated watercourses and other watercourses would be reduced by use of appropriate pollution prevention measures and covered in the Construction Environmental Management Plan (CEMP). 8.10.3 During the construction phase there would be a neutral effect on habitats of negligible value within the soft estate and their associated protected species. Potential effects on protected species would be reduced by appropriate seasonal timing of works, translocation, and ecological watching brief, habitat enhancement and creation, where appropriate. Where required, protected species licences will be obtained prior to works. 8.10.4 The construction phase impacts of the scheme are considered to be slight adverse on great crested newts. The impact on this species will be reduced by appropriate mitigation measures, including those to be covered by EPS licensing. 8.10.5 Overall the scheme is considered to have a „slight adverse‟ effect on ecological resources resulting from loss and severance of negligible value habitat within the soft estate and reduction of buffering of adjacent designated sites and severance of habitat within the HA soft estate that, although itself is of negligible value, contributes to the habitat of protected species, but this is not considered significant. 8.10.6 A separate assessment (AIES) has concluded that this scheme does not result in a risk of likely significant effects on any Natura 2000 sites and therefore does not require „Appropriate Assessment‟.
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9. Geology and Soils 9.1 Emerging Guidance 9.1.1 The scope of assessment for Geology and Soils has been prepared in light of the emerging guidance as noted in HA200/08 and IAN125/09. This sees Contaminated Land, which was previously included in Geology and Soils, merging into the new Materials Chapter (Chapter 10). Therefore, Contaminated Land issues will no longer be considered within the Geology and Soils Chapter. 9.2 Study Area 9.2.1 The Study Area extends 500 metres on either side from the centre line of the Project. The significance of effects is considered within the area that can reasonably be expected to be affected by construction and operation of the proposed works. 9.3 Baseline Conditions Geology 9.3.1 The solid geology and drift deposits within the Study Area were identified using British Geological Survey maps of scale 1:50,000, Solid and Drift Edition, Sheet 239: Hertford (1978), Sheet 240: Epping (1996) and Sheet 257: Romford (1996). 9.3.2 The solid geology underlying the Study Area is predominantly London Clay. 9.3.3 The surface drift deposits vary along the Study Area; it largely comprises gravel deposits such as Pebble Gravel, Valley Gravel and Glacial Gravels. Alluvium is also present, associated with rivers such as the River Lee. Isolated outcrops of Boulder Clay as well as Head and Old Head Drift deposits are also present. The table below presents the geology across the Study Area Table 9.1 - Geology Across the Project Strata Junctions 23-24 Junctions 24-25 Junctions 25-26 Junctions 26-27 Drift Deposits Pebble Gravel Alluvium Alluvium Head Valley Gravel Valley Gravel Valley Gravel Old Head Boulder Clay Glacial Gravel Boulder Clay outcrops Boulder Clay outcrop Pebble Gravel Solid London Clay London Clay London Clay London Clay
Clay Gate Beds
Aquifers 9.3.4 The majority of the underlying lithology is defined as a non-aquifer; this is attributed to the London Clay. Between Junctions 25 to 26, a major aquifer of high leaching potential is present which is likely to be attributed to the Valley Gravel. 9.3.5 An outer and inner Groundwater Source Protection Zone associated with a groundwater abstraction borehole is located west of Junction 25.
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9.3.6 A minor aquifer of intermediate leaching potential and low leaching potential is located west of Junction 27. Designated Sites 9.3.7 There are no designated Regionally Important Geological/Geomorphological Sites (RIGS) or Geological/Geomorphological SSSIs within the Study Area. 9.3.8 The majority of the Study Area is not considered to be valuable/sensitive in terms of geological receptors/resources. However, localised areas of sensitivity include the Groundwater Source Protection Zone (inner and outer) west of Junction 25 and the major aquifer present between Junctions 25 to 26. Geology and Soils Features 9.3.9 Geological and soil features within the Study Area are summarised in Table 9.2 and illustrated in Figure 9.1. Table 9.2 - Geological and Soil Features within Study Area Attribute (feature) Example Number of Occurrences within 500 metre Study Area Designated geological/ RIGS There are no designated geomorphological sites geological/geomorphological sites within the Study Area. SSSI There are no designated geological/geomorphological sites within the Study Area. Local soil resource Grade 1 agricultural land There are no areas of Grade 1 agricultural (excellent) land within the Study Area. Grade 2 agricultural land There are no areas of Grade 2 agricultural (very good) land within the Study Area. Grade 3 agricultural land There are several areas of Grade 3 land (moderate) within the Study Area. Grade 4 agricultural land There are several areas of Grade 4 land (poor) within the Study Area. Grade 5 agricultural land There are no areas of Grade 5 agricultural (very poor) land within the Study Area. Quarries and Mines Active mines and quarries There are no active mines and quarries within the Study Area. Controlled Water Surface Water: Rivers, There are several surface water bodies which Brooks cross the Project: Mimmshall Brook, Turkey Brook, Cuffley Brook, Cobbin‟s Brook, Brookhouse Brook New River, and River Lee Navigation. The associated floodplains of Mimmshall Brook, River Lee, Cobbin‟s Brook, River Lee Navigation, and Brookhouse Brook also cross the M25. Groundwater The majority of the Project is underlain by a non aquifer which can be attributed to the London Clay. Non aquifers are formations which are regarded as containing insignificant quantities of groundwater
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Attribute (feature) Example Number of Occurrences within 500 metre Study Area A major aquifer of high leaching potential is located between Junction 25 and 26. As well as an outer and inner Groundwater Source Protection Zone west of Junction 25. Minor aquifer of intermediate leaching potential and low leaching potential is located west of Junction 27.
Topography 9.3.10 In general, the land varies from a height of 120 metres Above Ordinance Datum (AOD) at Junction 24 to the lowest point at 27 metres AOD at Junction 25. 9.3.11 The land is at 100 metres AOD at Junction 23 and drops to 87 metres AOD east of Junction 23, where the Mimmshall Brook dissects the motorway. This height increases to 120 metre AOD at Junction 24 and drops to 27 metres AOD at Junction 25, where the motorway crosses the New River. The remaining land height is at 50 metre AOD at Junction 26, 100 metres east of Junction 26 and 40 metres AOD at Junction 27. Agricultural Land Quality 9.3.12 DEFRA‟s Agricultural Land Classification (ALC) system indicates the agricultural quality of soil. For the 500 metre corridor, reference has been made to the government‟s „Magic‟ website. The ALC system grades the land on a scale of 1 to 5, where 1 is the highest quality of agricultural land and 5 is the lowest. 9.3.13 Within the Study Area, the agricultural land area is classified as Grade 3 and Grade 4. Grade 3 land can be described as „Moderate‟ quality agricultural land, while Grade 4 can be described as „Poor‟ or „Not Best and Most Versatile‟ agricultural land. There are no areas of „Best and Most Versatile‟ agricultural land within the Study Area. Quarries and Mines 9.3.14 Information on quarries and mines within the Study Area has been obtained from the Environment Agency website, relevant local authorities and from the British Geological Survey website. 9.3.15 Although there are a number of historical quarries within the Study Area, there are no active quarries or mines. Motorway Cutting and Embankments 9.3.16 The locations of cuttings are of particular importance where the Project passes through an aquifer or areas of contaminated land. This is particularly important between Junctions 25 and 26, as two adjacent historical landfill sites are present on the northern boundary of the motorway. 9.3.17 This area also coincides with a major aquifer of high leaching potential. This is also an inner Groundwater Source Protection Zone and an outer Groundwater Protection Zone. 9.3.18 Contaminated land is discussed in more detail in Chapter 10: Materials. The location of landfill sites are shown in Figure 10.1. 9.4 Methodology 9.4.1 The simple assessment methodology used follows the requirements of DMRB Vol 11, Section 2 Part 5 (HA205/08). This forms an assessment of geology, geomorphology and soils. Impacts to contaminated land are assessed in Section 10 – Materials. The significance criteria in this assessment have been developed specifically for this Project, as there are no significance criteria for Geology and Soils in DMRB.
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9.4.2 The initial phase was the establishment of baseline conditions within the Study Area. An assessment of the potential direct and indirect impacts of the Project on the geology and soils was then carried out. 9.4.3 Information used to derive the baseline condition has been obtained from the following statutory and regulatory websites: Environment Agency www.environment agency.gov.uk. British Geological Survey www.bgs.ac.uk. Government „Magic‟ www.magic.gov.uk. 9.4.4 An Envirocheck report has also been obtained. Value of Environmental Resources and Receptors 9.4.5 The criteria in Table 9.3 were used to assess the importance of individual geological and soils features within the Study Area. Table 9.3 - Value of Geological and Soil Attributes Value (sensitivity) Typical Descriptors Very High High importance and rarity, international scale and limited potential for substitution High High importance and rarity, national scale and limited potential for substitution Medium High or medium importance and rarity, regional scale, limited potential for substitution Low (or Lower) Low or medium importance and rarity, local scale Negligible Very low importance and rarity, local scale
Magnitude of Impact 9.4.6 The magnitude of impact of the Project has been defined by the criteria shown in Table 9.4. The magnitude of the impact was cross-referenced with the value (importance) of a feature or resource to determine the significance of effect. Table 9.4 - Definition of Magnitude of Impact Magnitude of Criteria Impact Major Results in loss of attribute; or Results in high or very high risk of irreversible pollution to controlled water; or Results in high or very high risk to human health. Moderate Results in change on integrity of attribute or loss of part of attribute; or Results in moderate pollution or moderate risk to controlled water or human health. Minor Results in minor change on attribute, or Results in short term deterioration in quality of, or minor risk to, controlled waters. Negligible Results in negligible pollution of, and negligible risk to, controlled water. Results in negligible risk to human health Results in a change on attribute but insufficient magnitude to affect the use/integrity. No Change No loss or alteration of characteristics, features or elements No observable impact in either direction
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Significance of Effect 9.4.7 Using the resource value and magnitude of impact criteria set out in Table 9.3 and Table 9.4, the determination of Significance of Effect is defined in Table 9.5. Table 9.5 - Definition of Significance of Effect Magnitude Value of Attribute of Impact Very High High Medium Low Negligible Major Very Large Large or Very Moderate or Slight or Slight Large Large Moderate Moderate Large or Very Moderate or Moderate Slight Neutral or Large Large Slight Minor Moderate or Slight or Slight Neutral or Neutral or Large Moderate Slight Slight Negligible Slight Slight Neutral or Neutral or Neutral Slight Slight No Change Neutral Neutral Neutral Neutral Neutral
9.4.8 When the magnitude of the impact on all the attributes is considered, an overall effect can be determined. The overall assessment categories are defined in Table 9.6. Table 9.6 - Definition of Significance of Effect
Score Comment Large Beneficial Project could have a large positive effect if it is predicted that it would result in Effect a „highly‟ significant improvement to a geological attribute(s) or „highly‟ significant improvement of pollution from contaminated land, with insignificant adverse effects on other geological and soils attributes. Moderate Beneficial Where the Project provides an opportunity to enhance the geology and soils Effect environment, because it results in predicted: Significant improvements on controlled waters or risk to human health from contaminated land Significant improvements for at least one geology or soils attribute, with insignificant adverse impacts on other attributes Very or highly significant improvements, but with some adverse effects of a much lower significance The predicted improvements achieved by the Project should greatly outweigh any potential negative effects Slight Beneficial Where the Project provides an opportunity to enhance the geology and soils Effect environment, because it provides improvements in geology and soils attributes which are of greater significance than the adverse effects. Neutral Where the net impact of the Project is Neutral, because: They have no appreciable effect, either positive or negative, on the identified attributes They have no appreciable effect, either positive or negative, on controlled waters or human health from contaminated land The Project would result in a combination of effects, some positive and some negative, which balance to give an overall Neutral effect. In most cases these would be slight or moderate positive and negative effects. It may be possible to balance effects of greater significance, however, in these cases great care would be required to ensure that the effects are comparable in terms of their potential environmental impacts and the perception of these effects.
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Score Comment Slight Adverse Where the Project may result in a degradation of the geology and soils Effect environment, because the predicted adverse effects are of greater significance than the predicted improvements. Moderate Adverse Where the Project may result in a degradation of the geology and soils Effect environment, because it results in predicted: Significant effects on controlled waters or human health from contaminated land Significant adverse effects on at least one attribute, with insignificant predicted improvements to other attributes Very or highly significant adverse effects, but with some improvements which are of a much lower significance and are insufficient positive effects to offset the negative effects of the Project Large Adverse Where the Project may result in a degradation of the geology and soils Effect environment, because it results in predicted: Highly significant effect on controlled waters or human health from contaminated land Highly significant adverse effects on a geology and Soils attributes Significant adverse effects on several geology and Soils attributes Very Large Adverse Where the Project may result in a degradation of the geology and soils Effect environment because it results in predicted: Very significant effect on controlled waters or human health from contaminated land Very significant adverse effect on at least one geology and soils attribute Highly significant adverse effects on several geology and soils attributes 9.5 Value (Sensitivity) of Resource 9.5.1 The value of geological and soil attributes present within the Study Area is set out in Table 9.7 below. This is derived using the value criteria and descriptors set out in Table 9.3. Table 9.7 - Value of Geological and Soil Attributes within the Study Area
Resource Attribute Importance Group Very High Medium Low Negligible High
Local soil Grade 3 resource Grade 4 and 5 agricultural land
Existing highway land
Hydrogeology Major Aquifer/SPZ
Minor Aquifer 9.6 Regulatory/Policy Framework National Policy The Water Resources Act (1991) 9.6.1 The Water Resources Act 1991 (WRA) replaced the corresponding sections of the Water Act 1989. The WRA sets out the responsibilities of the Environment Agency in relation to water pollution, resource management, flood defence, fisheries, and in some areas, navigation. The
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WRA regulates discharges to controlled waters, namely rivers, estuaries, coastal waters, lakes and groundwaters. Groundwater Regulations (1998) 9.6.2 The Groundwater Regulations are an environmental protection measure which complete transposition of the Groundwater Directive (80/68/EEC) and provide enhanced protection for groundwater. Under the Regulations, the Environment Agency has responsibility for the enforcement of the Regulations and decisions of their scope and effect. The Environmental Protection (Duty of Care) Regulations (1991) 9.6.3 The Duty of Care Regulations takes on the responsibilities of the Environmental Protection Act for the safe disposal of wastes and devolves the responsibility to the manufacturer of the waste. All companies that produce waste are affected by this legislation. Persons concerned with controlled waste must ensure that the waste is managed properly, recovered or disposed of safely, does not cause harm to human health or pollution of the environment and is only transferred to someone who is authorised to receive it. The duty applies to any person who produces, imports, carries, keeps, treats or disposes of controlled waste or as a broker has control of such waste. CL:AIRE The Definition of Waste: Development Industry Code of Practice 9.6.4 This Code of Practice (CoP) provides best practice for the development industry to use when assessing if materials are classified as waste, or not, and determining when treated waste can cease to be waste for a particular use. The CoP provides engineers, contractors, consultants and developers a basis upon which to demonstrate to the Environment Agency that they are following best practice with respect to the use and reuse of materials. It provides an auditable system to demonstrate that the CoP has been adhered to on a site by site basis. The development and use of the CoP is seen as a Better Regulation Approach by the EA. 9.6.5 The CoP requires a normal risk assessment based approach (see CLR 11 above) to prove that materials are “suitable for use”. Where materials are not considered to be waste the Environmental Permitting Regulations (2007) need not be applied. Soils requiring treatment to allow their re-use are considered to be waste. Such treatment processes must be undertaken under an appropriate Mobile Treatment Permit. The CoP allows the user to demonstrate when wastes have been fully recovered, via treatment, and hence cease to be waste. Local Policy Borough of Broxbourne Local Plan 9.6.6 Borough of Broxbourne Local Plan (Borough of Broxbourne, 2005) includes Policy SUS3: Waste and Recycling which states that: (i) When considering development proposals, the council will encourage the re-use of excavated material from construction projects, including from the proposed development itself, as preparation for development, land restoration or site landscaping and where possible the use of recycled aggregates and building products within building and other structures in preference to natural aggregates or previously unused materials. (ii) Facilities sufficient to permit the separation and storage of different types of waste prior to collection will also be encouraged. 9.6.7 It also contains Policy SUS5: Pollution which states that: (i) in considering proposals for potentially hazardous or polluting development, the council will assess the following: (a) the ability to separate the location of the proposed use from other pollution sensitive land uses to reduce conflict. the council will take into account existing land uses and areas designated in the plan for these pollution-sensitive uses.
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(b) the possible impact of the development on land use including the effects on health, the natural environment, or general amenity resulting from release to water, land or air, or of noise, dust vibration, light or heat; (c) the wider economic and social need for the potentially polluting development. (d) the feasibility of securing pollution and nuisance controls during the lifetime of the use, and restoration of the land so that it is capable of an acceptable and safe after-use. Epping Forest District Plan 9.6.8 Epping Forest District Plan (Epping Forest District Council, 2008) includes Policy RP5 which states that: The council will not grant planning permission for: (i) development close to existing residential areas, hospitals and schools where the new development could cause excessive noise, vibration, or air, ground or light pollution; or (ii) sensitive development such as housing, hospitals or schools which could be subject to either excessive noise from adjoining land uses or traffic, or other forms of nuisance; except where it is possible to mitigate the adverse effects by the imposition of appropriate conditions. 8.21 Consultations with the Council's Environmental Services and other pollution authorities will be carried out in determining any planning application. Consideration will be given to the possibility of granting planning permission subject to conditions covering such issues as: (i) traffic movements during and after construction; (ii) daily cleaning of access highways and other techniques to minimise dust emissions during construction; (iii) days and hours of operation or use of the completed development; and (iv) noise and vibration from plant and machinery. Welwyn and Hatfield Local Plan The Welwyn and Hatfield District Pan (2005) has policy R5 – Waste management which states “the council will require applications for larger schemes (as defined in para 5.24) to include details of the measures taken in the design, construction, operation, occupation and demolition of existing buildings on site to;(i) minimise the amount of waste generated (ii) re use or recycle suitable waste material (iii) minimise the pollution potential of unavoidable waste (iv)treat and dispose of the remaining waste in an environmentally acceptable manner and (v) to maximise utilisation of appropriate secondary construction, materials, including recycled aggregates” 9.7 Design, Mitigation and Enhancement Measures Design 9.7.1 It is proposed that a sheet piled retaining wall is adopted. At some locations it is suggested to remove the alluvial deposits to avoid slope failure. The location of floodplains is an important factor that has been taken into consideration for the proposed geotechnical solutions. 9.7.2 Gantry foundations are likely to be up to 10 metres wide and piled. A site investigation would be required to confirm the location of made ground, landfill areas, material strength and suitability of soils and London Clay. In the Lea Valley area detailed ground investigation is required, in particular as the London Clay is likely to thin in this area providing less protection to groundwater.
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Mitigation 9.7.3 The presence of contamination is identified as the most significant impact in terms of geology and soils. Mitigation measures for contaminated land are outlined in Chapter 10: Materials. These measures to be taken would be detailed in the CEMP. This would be produced by the DBFO Contractor prior to construction. In addition to the contaminated land measures, mitigation for geology and soils would include the following: Use of water to prevent the creation of dust which would have an adverse effect on watercourses, construction workers and nearby residential properties Avoid locating cabins and material stores on floodplains of watercourses where possible. Excavated Material Identify potential locations for the safe storage of stockpiles and spoil heaps Storage locations should be considered if there is sufficient space for large volumes of material to be stored on site for longer periods of time 9.7.4 Volumes of imported and exported spoil material for earthworks have been estimated in Chapter 10: Materials. The DBFO Contractor would determine how much of this material would be re- used, where it would be stored, where it would be disposed to and where imported material would be sourced from. Therefore these effects cannot be assessed at this time and will need to be reassessed at the time of detailed design, as these construction details are not available. However, the earthworks strategy would be to: Maximise re-use of material Minimise import and export of material Minimise disposal of waste in landfill
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9.8 Magnitude of Impacts (Change) 9.8.1 After consideration of all the features included in the geology and soils assessment, the greatest impact arising from geology and soils assessment is found to be from potentially contaminated land. This is discussed in Chapter 10: Materials. 9.8.2 As stated in Section 9.3, there are no designated geological or geomorphological sites, active mines, quarries or active landfill sites within the Study Area. Table 9.8 and Table 9.9 summarise the magnitude of impacts identified for the Project during both the construction and operational phases. Construction Phase
Table 9.8 - Predicted Magnitude of Impacts during Construction Phase
Attribute/Feature Predicted Impacts Magnitude of Impacts
Geology There are no significant geological outcrops which will be Neutral impacted by the Project.
Local Soil Resource Import and export of soil for geotechnical solutions would Negligible cause extra transport pollution. The likelihood exists that there will be increased works traffic for the proposed geotechnical solutions. This will increase traffic emissions and dust with the potential for settling in the surrounding soil. Water will be also be used to damp down the dust and again there is potential for direct infiltration into soil. The surrounding land is classified as Grade 3 Moderate or Not Best and Most Versatile Agricultural Land. With the correct mitigation measures outlined taken this impact will be reduced to negligible.
Increased works traffic and equipment for example tippers Negligible and excavators. Issues of refuelling and oil spillage seeping into surrounding soil. The surrounding land is classified as Grade 3 Moderate or Not Best and Most Versatile Agricultural Land. With the correct mitigation measures outlined taken this impact will be reduced to negligible.
Water used to damp down dust will lead to increased run-off Negligible of water, taking with it any oil spillages, which could reach brooks, such as the Mimmshall Brook.
With the correct mitigation measures outlined taken this impact will be reduced to negligible. Groundwater A large area is underlain by London clay; a negligibly permeable aquifer and thus any contaminants present would not affect groundwater. However, there are areas underlain Minor by minor aquifers of low and intermediate leaching potential and major aquifers of leaching potential. Where sample testing exceeded drinking water guidelines, there is potential for contaminants to reach groundwater. Appropriate mitigation measures should be taken in order to prevent this from occurring.
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Operational Phase
Table 9.9 - Predicted Magnitude of Impacts during the Operational Phase Attribute/Feature Predicted Impacts Magnitude of Impacts Geology There are no significant geological outcrops which will Neutral be impacted by the Project. Local Soil Increase in overall amount of traffic Negligible Resource This will lead to an increase in the settling of atmospheric pollution from traffic into surrounding. Agricultural land is classified as Grade 3 and 4 and Urban. Therefore, it is not considered to be best and most versatile agricultural land. This will have a negligible impact. Increase in overall amount of traffic Negligible This will lead to an increase in road surface gritting (winter). Potential run-off into the surrounding soil. Agricultural land is classified as Grade 3 and 4 and Urban. Therefore, it is not considered to be best and most versatile agricultural land. This will have a negligible impact. Increase in overall amount of traffic Negligible This will potentially lead to an increase in road spillages and accidents (localised) which have the potential to leach into surrounding soil. Agricultural land is classified as Grade 3 and 4 and Urban. Therefore, it is not considered to be best and most versatile agricultural land. This will have a negligible impact. Increase in amount of gantry maintenance traffic Negligible and works traffic There will be an increase in the amount of gantry maintenance traffic and works traffic due to an overall increase in the amount of gantries. This will lead to an increase in road spillages and accidents (localised) has potential to leach into surrounding soil. Agricultural land is classified as Grade 3 and 4 and Urban. Therefore, it is not considered to be best and most versatile agricultural land. This will have a negligible impact. Controlled Water Attenuation storage will be provided to control discharge Negligible of surface water runoff into the water environment. This will lead to a slight increase in contamination to surface water. Groundwater is unlikely to be significantly affected due to presence of London Clay 9.9 Significant Effects Construction Phase 9.9.1 The significance of effects upon geology and soils attributes during the construction phase are shown in Table 9.10 below. 9.9.2 Degradation and potential loss of near surface geology, relate to the following: Providing ERAs - where ERAs are required along existing embankments, the import of material may be required. Where ERAs are required along existing cuttings, the cutting will need to be cut and re-profiled or retained using a geotechnical and/or structural solution to accommodate the ERA
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Foundations for gantry supports Foundations for additional lighting in verge Upgrade of the drainage system Excavation into potentially contaminated land 9.9.3 Additional motorway cuttings, embankments or construction of gantries may result in excavation of contaminated land and creation of contaminant migration pathways. This area is of particular concern due to the Major Aquifer and the presence of an inner and outer Groundwater Source Protection Zone. 9.9.4 Appropriate supplementary ground investigation should be undertaken in the location of earthworks/construction areas to define the specific design and hence the impact that each design will have on receptors (e.g. piled gantries/structures can pose a bigger risk to major aquifers by creating pathways). This ground investigation should take place when the footprint of the new construction is known. 9.9.5 The leachate potential of any replacement fill should be assessed to determine the risk to the receptors in particular the major aquifer. Table 9.10 - Significance of Effects during Construction
Attribute/Feature Predicted Impacts Significance of Effects
Geology There are no significant geological outcrops, which will be Neutral impacted by the Project. Local Soil Import and export of soil for geotechnical solutions would Neutral Resource cause extra transport pollution. The likelihood exists that there will be increased works traffic for the proposed geotechnical solutions. This will increase traffic emissions and dust with the potential for settling in the surrounding soil. Water will be also be used to damp down the dust and again there is potential for direct infiltration into soil. The surrounding land is classified as Grade 3 Moderate or Not Best and Most Versatile Agricultural Land. With the correct mitigation measures outlined taken this impact will be reduced to negligible. Increased works traffic and equipment for example diggers Neutral and excavators. Issues of refuelling and oil spillage seeping into surrounding soil. The surrounding land is classified as Grade 3 Moderate or Not Best and Most Versatile Agricultural Land. With the correct mitigation measures outlined taken this impact will be reduced to negligible. Water used to damp down dust will lead to increased run- Neutral off of water, taking with it any oil spillages, which could
reach brooks, such as the Mimmshall Brook.
With the correct mitigation measures outlined taken this impact will be reduced to negligible. Groundwater A large area is underlain by London clay; a negligibly permeable aquifer and thus any contaminants present
would not affect groundwater. However, there are areas underlain by minor aquifers of low and intermediate Slight Adverse leaching potential and major aquifers of leaching potential. Where sample testing exceeded drinking water guidelines, there is potential for contaminants to reach groundwater. Appropriate mitigation measures should be taken in order to prevent this from occurring.
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Operational Phase 9.9.6 The significance of effects upon geology and soils attributes during the operational phase are shown in Table 9.11 below. Table 9.11 - Significance of Effects during Operation Attribute/Feature Predicted Impacts Significance of Effects Geology There are no significant geological outcrops, which will be Neutral impacted by the Project. Local Soil Increase in overall amount of traffic Neutral Resource This will lead to an increase in the settling of atmospheric pollution from traffic into surrounding. Agricultural land is classified as Grade 3 and 4 and Urban. Therefore, it is not considered to be best and most versatile agricultural land. This will have a negligible impact. Increase in overall amount of traffic Neutral This will lead to an increase in road surface gritting (winter). Potential run-off into the surrounding soil. Agricultural land is classified as Grade 3 and 4 and Urban. Therefore, it is not considered to be best and most versatile agricultural land. This will have a negligible impact. Increase in overall amount of traffic Neutral This will lead to an increase in road spillages and accidents (localised) which have the potential to leach into surrounding soil. Agricultural land is classified as Grade 3 and 4 and Urban. Therefore, it is not considered to be best and most versatile agricultural land. This will have a negligible impact. Increase in amount of gantry maintenance traffic and Neutral works traffic There will be an increase in the amount of gantry maintenance traffic and works traffic due to an overall increase in the amount of gantries. This will lead to an increase in road spillages and accidents (localised) has potential to leach into surrounding soil. Agricultural land is classified as Grade 3 and 4 and Urban. Therefore, it is not considered to be best and most versatile agricultural land. This will have a negligible impact. Controlled Water Attenuation storage will be provided to control discharge of Slight Adverse surface water runoff into the water environment. This will lead to a slight increase in contamination to surface water. Groundwater is unlikely to be significantly affected due to presence of London Clay.
Significance of Effects on Plans and Policies 9.9.7 The Project wouldn‟t significantly affect any of the national, regional and local policies outlined in Section 9.6. The overall effects on geology and soils have been assessed as neutral to slight adverse during both construction and operational phases. In addition, mitigation measures to be adopted during the construction and operation phases of the Project will reduce these potential effects further. As a result, the Project would not materially affect geology and soil policies, leading to a Neutral effect.
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9.9.9 The policies expected to experience a neutral effect include: National - Water Resources Act; Groundwater Regulations; Environmental Protection (Duty of Care) Regulations and CL:AIRE (Office of Public Sector Information) Local - SUS 3 and SUS5 (Borough of Broxbourne Local Plan) RP5 (Epping Forest District Plan) 9.10 Indication of Any Difficulties Encountered 9.10.1 No difficulties have been encountered whilst undertaking this assessment. However, it should be noted that guidance on separating Geology and Soils and Contaminated Land was unavailable at the time of writing. 9.11 Summary 9.11.1 There are no designated geological or geomorphological sites, active mines, quarries or active landfill sites within the Study Area. The local agricultural soil is classified as grade 3 or 4 and has a medium and low importance respectively. Due to the major aquifer and source protection zone between Junctions 25 and 26, the hydrogeology has a high importance.A site investigation would be required to confirm the location of made ground, landfill areas, material strength and suitability of soils and London Clay. In the Lea Valley area detailed ground investigation is required in particular, as the London Clay is likely to thin in this area providing less protection to groundwater. Careful design of any deep foundations may be required to ensure no new pathway for surface water to enter groundwater is created. Following the site investigation, the risks to groundwater and controlled waters would be reduced resulting in an overall significance of effects for geology and soils of Neutral. 9.11.2 The general construction effects, for example, increased amounts of dust (which may cause a nuisance to the local residents and may enter surface water), can be avoided through the implementation of the CEMP. This would be produced by the DBFO Contractor prior to construction. 9.11.3 Many of the effects are caused as a result of construction relate to potential contamination. Contaminated land issues are discussed in Chapter 10: Materials. 9.11.4 The overall effects on the geology and soils have been assessed as Slight Adverse during both construction and operational phases. However, mitigation measures (as discussed in Section 9.7) can be adopted during the construction and operation phases of the Project, which will reduce the potential impact to Neutral.
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10. Materials 10.1 Guidance and Introduction 10.1.1 The scope of assessment for materials has been prepared in light of the emerging guidance as noted in HA200/08 and IAN153/11. This sees the original chapters for „Disruption due to Construction‟ and the Contaminated Land element of „Geology and Soils‟ merging into ‟Materials‟. The Soils element forms part of the Chapter 9 „Geology and Soils‟ of this EAR in accordance with IAN125/09. 10.1.2 Land contamination can present an unacceptable risk to a scheme, or the scheme itself may increase a risk that existing land contamination already poses. The preliminary assessment undertaken follows procedures for the management of land contamination (Contaminated Land Report (CLR) 11), which is the Environment Agency‟s key guidance document on the assessment, management and implementation of remediation within the UK. It provides a technical framework for risk management of land contamination to comply with appropriate legislation as detailed below. 10.1.3 Therefore, a preliminary conceptual site model has been prepared to aid in identification and assessment of potential effects of the proposed scheme and any land contamination present. A conceptual site model describes the relationship between potential sources of contamination (resulting from both on-and off-site historical and recent activities) and receptors which could be exposed to the potential contamination. As part of the conceptual site model development, three elements, the source of contamination and associated contaminants, receptors to that contamination and the pathways by which such exposure can take place, are identified and assessed. Where all three elements are present or are likely to be present, they are described as potential contaminant linkages. 10.1.4 The activities considered in the assessment are the construction of emergency refuge areas and the proposed gantry construction locations. Appropriate Legislation Part 2A Contaminated Land 10.1.5 Part 2A came into force in England in 2000 and Wales in 2001 and was implemented under the Environmental Protection Act. Parts 2A addresses the legacy of land contamination and its core elements are: establishment of a risk based and legal definition of “contaminated land”. Land which is deemed to be contaminated land is determined by the Local Authorities of England and Wales when (i) the land is causing significant harm, or there is the significant possibility of such harm to human health or the environment; or (ii) it is causing or likely to cause pollution of controlled waters. Part 2A placed a duty on Local Authorities (as a primary regulator) to inspect their borough‟s in order to identify contaminated land, if contaminated land was identified there is a requirement to remediate, where possible. It also makes the Environment Agency (as a secondary regulator) responsible for “special sites” (sites where there are certain types of water pollution or radioactive contamination) and allows the Environment Agency a role as technical advisor; it sets out the rules on who should pay for remediation, with the polluter being the person most responsible, followed by the landowner. The local authority (or Environment Agency) may be required to bear costs if these parties cannot bear the costs. it allows for retrospective liability where polluters and landowners are liable for historical land contamination.
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Waste Framework Directive 10.1.6 The Waste Framework Directive (WFD) is the primary European Legislation for the management of waste. It sets out the overarching legislative framework for the collection, transport, recovery and disposal of waste. EU Member States are required to lay down appropriate measures to ensure that waste is recovered or disposed without endangering the environment or human health. The directive specifies permitting, registration and inspection requirements. In addition Member States are required to take measures in the first instance to encourage the prevention/ reduction of waste production, and secondly the recovery of waste through recycling, reuse, reclamation or energy recovery. Revised Waste Framework Directive (2008/98/EC) 10.1.7 Revisions to the Waste Framework Directive (rWFD) were adopted in December 2008, with Member States being required to implement the revisions by December 2010. 10.1.8 The aim of the revised rWFD is to promote waste prevention, increase recycling and ensure the better use of resources whilst protecting the environment and human health. Greater emphasis is placed on the waste hierarchy to ensure that waste is managed within the following priority order: prevention; preparing for re-use; recycling; other recovery (for example, energy recovery); disposal. 10.1.9 Further key revisions include: establishing Waste Prevention Programmes describing existing prevention measures, evaluating the usefulness of other measures and determine benchmarks for measurement of adopted prevention measures. promoting the high quality recycling of waste materials as part of the overall aim to make the EU a „recycling society‟. ensuring that separate collection is set up for at least the following: paper, metal, plastic and glass by 2015, “where technically, environmentally and economically practicable and appropriate”. (The UK has clarified that co-mingled collection can continue after 2015 where this is the best means of increasing recycling rates in local circumstances). preparing for reuse and the recycling of waste materials such as paper, metal, plastic and glass from households shall be increased to a minimum of overall 50% by weight by 2020. preparing for reuse, recycling and other material recovery of non-hazardous construction and demolition waste shall be increased to a minimum of 70% by weight in 2020. establishing an integrated and adequate network of waste disposal installations, and installations for the recovery of mixed household waste. ensuring that waste management is carried out without endangering human health and without harming the environment. establishing waste management plans. 10.1.10 The rWFD repeals and integrates the provisions of both the Hazardous Waste Directive and the Waste Oils Directive.
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10.2 Study Area and Baseline Conditions 10.2.1 Figure 10.1 provides the location of known areas of potentially contaminated material (i.e. Made Ground, landfilled waste or other potentially contaminative current or former land uses). These areas are identified in drawing numbers: 001 to 008. They form the primary focus of this assessment and have been cross-referenced against areas where excavation activities will be undertaken as part of the overall Scheme. 10.2.2 This chapter therefore focuses on those locations where the footprint of a construction activity is located within an area where potentially contaminated materials have been identified from Figure 10.1, these are: „other potential source of contamination‟ (reference number 5) between chainage 51500 to 52000; „historical mineral extraction‟ (reference number 6, 7 and 8) between chainage 52000 to 52600; „Made Ground‟ (reference number not given, but located immediately south of reference number 12) between chainage 5350 and 53500; „‟historical landfill‟ (reference number 13) between chainage 53500 and 53750; „Made Ground‟ (reference number 15) between chainage 55750 and 56500; „Made Ground‟ (reference number 17) between chainage 58000 and 58200; „Made Ground‟ (reference number 21) between chainage 60000 and 60100; „Made Ground‟ (reference number 22) between chainage 6100 and 62450.
10.2.3 The areas of construction outside of these features have not been considered as part of this assessment. 10.3 Assessment 10.3.1 The assessment is split into three sections, namely: potential contaminant sources; receptors; and potential contaminant pathways. 10.3.2 Following the identification of potential sources, receptors and pathways, a preliminary risk estimation has been provided, followed by a conceptual site model in tabular format. Potential Contaminant Sources 10.3.3 The potential contaminant sources are the areas identified in Section 10.2. The contaminated land features identified in Figure 10.1 have been identified from previous investigations undertaken across the route and historical land use records. 10.3.4 The sources comprise a range historical land uses including landfill sites and spoil tip areas, with the potential for a range of contaminants to be present including asbestos, heavy metals, hydrocarbons, volatile organic compounds, landfill gas and landfill leachate. For example the Environment Agency Website indicates that the „Former Enfield Sewage Works‟ landfill site, in the areas of „historical mineral excavation‟ (reference numbers 6,7 and 8 on Figure 10.1), was licensed to accept a variety of waste including household waste, industrial wastewater, sewage sludge and chemical wastes mixed with municipal solid waste. 10.3.5 Limited site investigation data, including chemical analysis results, are available for selected identified source areas. At this stage these data have not been assessed as part of this preliminary assessment as there is currently insufficient information to robustly increase the
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confidence of the preliminary assessment. Future assessments shall include an appraisal of these data, along with any additional data collected as part of further intrusive investigations. These intrusive investigations shall be designed to compliment existing data and also provide specific information at the sites of construction. Known Receptors 10.3.6 The assessment of risk to known receptors is based on consideration of the works to be undertaken as part of the scheme and future site users. Human Health 10.3.7 Due to the proposed end use of the site as part of the active road network the risk for long term exposure of potential contaminants to human health receptors is considered highly unlikely. 10.3.8 It should be noted that under current health and safety legislation, companies undertaking construction and maintenance works are required to carry out appropriate risk assessments and instigate appropriate mitigating measures to protect their employees, other people who could be exposed through the works and the environment from contamination which may be present. Such risks must be adequately mitigated by the measures required under current legislation, specifically the Construction Design and Management (CDM) Regulations, 2007 which require that potential risks to human health and the environment from construction activities are appropriately identified and all necessary steps taken to eliminate / manage that risk. 10.3.9 Human health, in relation to the exposure to contaminants within the soil or any ground/perched water has therefore not been considered as part of this assessment. Controlled Waters 10.3.10 Previously identified sources are in close proximity to controlled waters, including surface water bodies, aquifers and Source Protection Zones (SPZ) are as follows: Four main surface water bodies (Small River Lee, River Lee, River Lee Navigation Channel and Cobbins Brook) and several drainage channels/ unnamed streams; Source references 6, 7, 8 and 12 are within an Inner Zone (Zone 1) SPZ. Source references 5 and 13 are within an Outer Zone (Zone 2 SPZ); and Source references 5, 6, 7, 8, 12 and 13 are underlain by a Secondary A Aquifer within the superficial Valley Gravel deposits. Source reference 21 is underlain by a Secondary A Aquifer within the Claygate Member bedrock. 10.3.11 The water environment is discussed in detail in Section 14. 10.3.12 Excavation and construction in the identified source areas may, in the short term, negatively impact the following identified waters receptors: Surface water courses (Primarily Small River Lee, River Lee, River Lee Navigation Channel and Cobbins Brook) Secondary A Aquifers in the superficial deposits and bedrock geology (Primarily underlying source references 5, 6, 7, 8, 12, 13 and 21 from Figure 10.1). 10.3.13 Following the works the removal of soils within the source areas may lead to environmental betterment. Built Environment 10.3.14 Buildings receptors considered within this assessment comprise: Road construction material; and, Buried services and structures
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Potential Contaminant Pathways 10.3.15 The potential pathways between the potential sources and receptors identified above are summarised below. Controlled Waters Leaching/dissolution of contaminants from soil followed by migration to groundwater; Lateral migration of contaminants from soil with groundwater flow to surface water bodies; and, Migration of leachable contaminants from soil along service corridors/ drainage Built Environment Direct contact with potentially contaminated soils; Direct contact with potentially contaminated landfill leachate/ shallow groundwater; and, Build up of ground borne/ landfill gas in enclosed spaces. Risk Estimation 10.3.16 Risk estimation has two components: Probability assessment – the probability relates to whether pollution/harm will occur in the short and/or long term. Risk estimation is only undertaken when a source-pathway-receptor linkage exists. Consequence assessment - the magnitude of harm that would occur due to the source- pathway-receptor exists, i.e. the degree of harm/pollution considering the sensitivity of the receptor.
10.3.17 As there is currently insufficient specific and relevant data available on the types and concentrations of land contamination at a site, a qualitative contaminated land risk assessment has been undertaken using a „matrix approach‟ (see Table 10.1) which accounts for the probability and consequence associated with the identified pollutant linkages.
Table 100.1 - Estimation of the Level of Risk by Comparison of Consequence and Probability
Consequence
Severe Medium Mild Minor
High Moderate/Low Very High Risk High Risk Moderate Risk Likelihood Risk
Moderate/Low Likely High Risk Moderate Risk Low Risk Risk
Low Moderate/Low Moderate Risk Low Risk Very Low Risk
Likelihood Risk Probability
Moderate/Low Unlikely Low Risk Very Low Risk Very Low Risk Risk
10.3.18 The descriptions of the classified risks are as follows: very high risk There is a high probability that severe harm could arise to a receptor from an identified hazard at the site without mitigating action OR there is evidence that severe harm to a designated receptor is already occurring. Realisation of that risk is likely to present a
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substantial liability to be site owner/or occupier. Investigation is required as a matter of urgency and remediation works likely to follow in the short-term. high risk Harm is likely to arise to a receptor from an identified hazard at the site without mitigating action. Realisation of the risk is likely to present a substantial liability to the site owner/or occupier. Investigation is required as a matter of urgency to clarify the risk. Remediation works may be necessary in the short-term and are likely over the longer term. moderate risk It is possible that harm could arise to a receptor from an identified hazard. However, it is either relatively unlikely that any such harm would be severe, and if any harm were to occur it is more likely that the harm would be relatively mild. Further investigative work is normally required to clarify the risk and to determine the potential liability to site owner/occupier. Some remediation works or mitigating action may be required in the longer term. low risk It is possible that harm could arise to a receptor from identified hazard, but it is likely at worst, that this harm if realised would normally be mild. It is unlikely that the site owner/or occupier would face substantial liabilities from such a risk. Further investigative work (which is likely to be limited) may be required to clarify the risk. Any subsequent mitigating actions are likely to be relatively limited. very low risk It is a low possibility that harm could arise to a receptor, but it is likely at worst, that this harm if realised would normally be mild or minor. no potential risk There is no potential risk if no pollution linkage has been established. 10.3.19 Table 10.2 summarises the potential sources, pathways and receptors identified above along with an estimated risk.
Table 100.2 - Conceptual Site Model
Source Pathway Receptor Assessed Risk Controlled Water
Leaching/dissolution of Secondary A Aquifers contaminants from soil Moderate/Low (superficial deposits and followed by migration to Risk bedrock) groundwater Identified Contaminated Land Lateral migration of Features as Section contaminants from soil Moderate/Low 10.2 – Comprising and landfill leachate with Surface water bodies Risk potentially groundwater flow to contaminated soil, surface water bodies. landfill leachate and ground borne/ landfill gas Migration of contaminants from soil Moderate/Low Surface water bodies and landfill leachate Risk along service corridors.
Built Environment
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Source Pathway Receptor Assessed Risk Identified Controlled Water C t i t d L d
Road construction Moderate/Low materials Risk
Direct contact with contaminants in soil and landfill leachate Buried services and Moderate/Low structures Risk
Migration and build up of Buried services and Moderate/Low ground borne/ landfill gas structures Risk in enclosed spaces
10.3.20 The preliminary conceptual site model suggests that there is currently a moderate/ low risk posed to the scheme from land contamination. 10.3.21 However the exact extent and nature of the material, within these features, is not known and further investigation and testing is required from within the potential source areas to inform the design and develop appropriately robust risk mitigation measures. Materials Management and Waste 10.3.22 It is considered likely that a combination of re-use of site won material and removal for off-site disposal will be required as part of the construction scheme. The legal framework for managing waste is detailed in Chapter 9 and Section 10.1 of this report. 10.3.23 There is currently insufficient information available to assess in detail the suitability of materials for re-use within the scheme and similarly the likely classification of waste soil for off site disposal. Further intrusive investigation and testing is required from within the potential source areas to inform the potential fates of site won material during construction. 10.4 Indication of Any Difficulties Encountered 10.4.1 No difficulties have been encountered whilst undertaking this assessment. However, it should be noted that guidance in the DMRB does not provide a suitable framework for evaluating the risks posed by land contamination and as such other relevant guidance (from the Environment Agency) has been used. 10.5 Summary 10.5.1 Based upon the potential sources of contamination from Figure 10.1 and the Scheme design and excavation areas (identified within Drawings: 001 to 008) there is a total of eight areas where potential contaminant sources may impact upon the Scheme. 10.5.2 Following Environment Agency guidance (CLR 11), a preliminary conceptual site model has been developed to initially appraise the risks from the potential sources to the known receptors. The following have been identified: Potential Sources: Eight sources, ranging from mineral extraction, Made Ground and a historical landfill Potential Pathways: Leaching/dissolution of contaminants from soil followed by migration to groundwater, lateral migration of contaminants from soil and landfill leachate with groundwater flow to surface water bodies, migration of contaminants from soil and landfill
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leachate along service corridors, direct contact with contaminants in soil and landfill leachate and migration and build up of ground borne/ landfill gas in enclosed spaces Potential Receptors: Secondary A Aquifers (superficial deposits and bedrock), surface water bodies, road construction materials and buried services and structures. 10.5.3 The assessment indicates that there is currently a moderate/low risk posed to the Scheme from land contamination. 10.5.4 Based on the available data, there is currently insufficient information available to be able to quantify robustly the risks associated with the Scheme and provide appropriate mitigation measures. 10.5.5 Further intrusive investigation will be required, in advance of the construction, to obtain site- specific information on the geology and hydrogeology beneath the site, together with collection of soil and groundwater samples for a range of contaminants within the potential source areas to provide quantitative data on the soil and groundwater quality. 10.5.6 Based on this information, the preliminary conceptual site model will be confirmed or revised and the risk posed by potential pollutant linkages assessed. In turn the risks posed during the construction and operational stage can be quantified from the chemical data and impacts assessed and mitigation measures identified.
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11. Noise 11.1 Study Area 11.1.1 The Study Area has been determined by the guidance contained within paragraph A1.11 of the Design Manual for Roads and Bridges Volume 11, Section 3, Part 7 – Noise and Vibration 2011 Revision 1 HD213/11 (DMRB). Paragraph A1.11 of DMRB details the methodology by which the affected routes are identified. 11.1.2 The DMRB requires calculations of noise impacts at locations within 600m of both the Scheme boundary, and within 600m of any other affected routes within 1km of the scheme boundary – this area is referred to as the detailed calculation area. 11.1.3 For affected routes outside the area where noise calculations have been undertaken, the study area is defined as 50m either side of the centreline of these routes. A route is considered as an affected route where it has a change in noise of more than 1dB(A) on opening, or of more than 3dB(A) over the design period – these routes are referred to as the wider road network, and form the wider calculation area. 11.1.4 This study is based on traffic forecasts prepared by Atkins. The traffic engineers have supplied data solely for the extents of the traffic model with reliable traffic predictions. 11.2 Baseline Conditions 11.2.1 The baseline noise conditions for the scheme were previously reported in the Stage 2 EAR document, and are summarised here for convenience. 11.2.2 It is understood that noise surveys were carried out at sixteen measurement locations in the vicinity of the scheme, and that the surveys were undertaken in accordance with the shortened measurement procedure outlined in the DoT technical memorandum Calculation of Road Traffic
Noise (CRTN). Measurements of LA10 were taken over fifteen minute periods in three consecutive hours between 10:00am and 5:00pm on a typical weekday. The arithmetic average of these
measurements was calculated and 1dB (A) subtracted to find the equivalent LA10,18-hour. 11.2.3 It was found that noise levels within 50 metres of the M25 were approximately 69 to 74 dB
LA10,18Hour. Beyond 50 metres, noise levels range from 57 to 65dB LA10,18Hour with other noise sources such as feeder roads tending to significantly contribute to the ambient noise climate. Noise levels at specific locations between Junction 24 to Junction 25 were higher than those experienced at other equivalent parts of the motorway and at Junction 26 to Junction 27. This was likely due to the concrete road surface in these areas between Junction 24 and Junction 25. The other parts of the M25 typically have either traditional hot rolled asphalt surfacing, or lower noise, thin wearing course surfacing. 11.3 Methodology Road Traffic Noise Assessment Methodology (Operational Impact) 11.3.1 The DMRB Simple Environmental Assessment methodology has been followed as appropriate for the Assessment of operational noise impacts: 11.3.2 This level of assessment methodology requires that the following comparisons are assessed. Opening Year (Short-term) Impacts – Do-minimum scenario in the baseline (opening) year, against Do-Something scenario in the baseline (opening) year, and Design Period (Long Term) Impacts – Do-minimum scenario in the baseline (opening) year, against Do-Something scenario in the future assessment (design) year.
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11.3.3 The noise model for calculating the operational impacts in the detailed calculation area has been built using the following source data; Ordnance Survey 10m ground contour PROFILE data– to define the ground topography in the scheme area; Ordnance Survey Master map style data – to obtain the locations of buildings and non- motorway roads in the scheme area; Scheme survey data to obtain the 3D position and alignment of the existing motorway and ground topography within the highway boundary; Scheme alignment drawings provided as .dwgs; Road surfacing details for the situation in 2012 have been provided by Skanska Balfour Beatty; Existing noise barriers have been modelled based upon information given within the 2009 EAR and visual information from Google Maps and Google Street View; 18Hour AAWT traffic data, and hourly AAWT traffic flow data covering the 24 hour period, output from the scheme traffic model, and Ordnance Survey Addresspoint style data – to identify residential properties and other noise sensitive receptors. 11.3.4 Calculations have been undertaken at the first floor of representative properties and other locations of interest within the detailed calculation area. These calculations have been undertaken at 4m above local ground level in accordance with the guidance in the DMRB. 11.3.5 Advice in DMRB or Calculation of Road Traffic Noise does not provide a method for assessing roads with mixed surfacing, and therefore the dominant road surface has been assumed at any given point along the carriageway, as within the previously submitted assessment. 11.3.6 In the Do Minimum and Do Something 2030 scenarios, it has been assumed that all carriageway running lanes, including the hard shoulders, would be surfaced with lower noise surfacing and a correction of -3.5dB(A) has been applied to all motorways. This assumption is based upon all of the carriageways requiring resurfacing by this time irrespective of the scheme, due to the expected life of a surface on a road carrying high volumes of traffic being no more than approximately 10 years. 11.3.7 The benefits of quieter road surfaces can currently only be taken into account when traffic speeds are above 75km/hr, and the calculations account for this accordingly. Reductions in noise are possible at lower speeds, but these are not supported by robust research. 11.3.8 Calculations for the detailed calculation area have been undertaken on the basis of the hourly
traffic flows provided, to calculate the LA10,18-Hour and Lnight at each location of interest. The LA10,18- Hour index represents the noise level during the daytime, covering the weekday period 06:00 through to midnight. The index is the arithmetic average of the 18 separate LA10,1hour calculations over this period. CRTN and DMRB provide the method for calculating the LA10,1hour. The Lnight index represents the noise level over the night, covering the period 23:00 to 07:00. The index is
the energy average of the 8 separate LAeq,1hour calculations over this period. The LAeq,1hour calculations are derived from the LA10,1hour calculations using the advice given in the DMRB. 11.3.9 Calculations for the wider calculation area have been undertaken on the basis of the 18-Hour AAWT traffic flows provided, to calculate a Basic Noise Level (BNL) for each traffic link, and identify any links predicted to experience significant changes in noise. The Basic Noise Level is
the LA10,18-Hour noise level expected at 10m from the edge of the road, taking into account the flow, composition and speed of the traffic on the road.
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11.3.10 The DMRB HD213/11 requires an assessment of night-time impacts, which should be undertaken
for dwellings where an Lnight, outside greater than 55dB is predicted to be experienced in any scenario. Construction Noise Assessment Methodology (Temporary Impact) 11.3.11 BS5228 Part 1:2009 - „Code of practice for noise and vibration control on construction and open site – Part 1: Noise‟, has been used to assess the potential for construction noise impacts arising from the scheme. Construction noise impacts have been estimated on the basis of typical plant itinerary and activities from previous assessments undertaken by Atkins for similar hard-shoulder running schemes. 11.4 Value (sensitivity) of Resource 11.4.1 The majority of the noise sensitive receivers in the area are residential properties. Other noise sensitive locations in the area include schools, registered parks and gardens, public rights of way heritage sites, and conservation areas. 11.4.2 DMRB, HD213/11 sets out example classifications of the magnitude of operational noise impacts for changes in noise experienced within both the short-term and long term. These are presented in Table 11.1 and Table 11.2 below. Table 11.1 - Descriptors for Magnitude of Noise Impacts in Short Term
Noise Change, LA10,18h Magnitude of Impact 0 No change 0.1 – 0.9 Negligible 1 – 2.9 Minor 3 – 4.9 Moderate 5+ Major
Table 11.2 - Descriptors for Magnitude of Noise Impacts in Long Term
Noise Change, LA10,18h Magnitude of Impact 0 No change 0.1 – 2.9 Negligible 3 – 4.9 Minor 5 – 9.9 Moderate 10+ Major
11.4.3 BS5228 Part 1:2009 - „Code of practice for noise and vibration control on construction and open site – Part 1: Noise‟, provides guidance on assessing the significance of noise effects from construction activities in its Annex E. 11.4.4 For the purpose of this report, the noise level change approach detailed in Annex E.3.2 of BS5228-1: 2009 has been used to form the significance criteria for the potential impacts from construction noise. 11.4.5 Subject to lower cut-on thresholds of 65dB during the day, 55dB during the evening and weekends, and 45dB during the night, a significant effect is deemed to have occurred if the total noise level with construction noise is 5dB or more above the noise level without construction noise.
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11.5 Regulatory/Policy Framework Noise Insulation Regulations 1975 (as amended) 11.5.1 Schemes which make alterations to roads usually require an assessment under the Noise Insulation Regulations 1975, amended 1988. These regulations give discretionary powers to provide noise insulation to residential properties when certain criteria are met. It is understood that HA policy will be not to apply those discretionary powers to managed motorway schemes, although this policy is subject to confirmation. Similar powers to give grants to moveable homes are given in the Highways Noise Payments and Movable Homes (England) regulations 2000 Land Compensation Act 1973 11.5.2 The Land Compensation Act makes provision for land owners and residents to apply for compensation if the value of their property has decreased as a result of the scheme. One of the factors which may be considered to affect the value is noise, and a change in noise is usually regarded as having a change in a property‟s value. The assessment of compensation is undertaken by the District Valuer, and the cumulative effect of all relevant factors must be considered in the assessment. The Environmental Noise (England) Regulations 2006 (as amended) 11.5.3 These regulations implement the European Commission Directive 2002/49/EC, which requires strategic noise maps and noise action plans to be produced for all sources of environmental noise, including that from road traffic using major roads. England's Noise Action Plans have identified 'Important Areas' at which measures to address environmental noise must be investigated, and those 'Important Areas with First Priority Locations' to be investigated as a priority. At the time of writing, it is understood that the Highways Agency has investigated all 'Important Areas with First Priority Locations' identified on its network and concluded that no specific noise mitigation measures, beyond the provision of low noise surfacing when required for maintenance reasons, are required for those Important Areas with First Priority Locations sited within early delivery managed motorway schemes.
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11.5.4 Figure 11.1 and Figure 11.2 below are derived from the Defra website, and identify in dark blue the areas containing Important Areas with First Priority Locations, and in light blue, other Important Areas. It can be seen that generally, all the residential areas and properties adjacent to the scheme are considered to be first priority or other Important Areas.
Figure 11.1 - Noise Action Plan Important Areas: M25 Section5 pt1
Figure 11.2 - Noise Action Plan Important Areas: M25 Section5 pt2
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Hansard Noise Hotspot Policy 11.5.5 In 1999, the Secretary of State undertook to consider road traffic noise at a number of sites, allowing a ring-fenced budget for treating the most pressing noise problems. The list was published in the parliamentary journal, Hansard. This area does not contain any of the locations in the list published in Hansard. National Planning Policy Framework 11.5.6 The National Planning Policy Framework provides guidance for considering noise impacts from development schemes, including roads. Planning decisions should avoid significant adverse noise impacts and reduce to a minimum other adverse impacts. The London Plan 11.5.7 The London Plan Policy 4 A.20 states that the Mayor and the London Boroughs in their Development Plan Documents, should reduce noise by, “minimising the existing and potential adverse impacts of noise on, from, within, or in the vicinity of, development proposals … supporting new technologies and improved practices to reduce noise at source, especially in road, rail and air transport … reducing the impact of traffic noise through highway management and transport policies … identifying areas of relative tranquillity which it is intended should be protected or enhanced.” The Mayor’s Ambient Noise Strategy 11.5.8 Section 4 A of the Mayor‟s Ambient Noise Strategy contains a number of policies aimed at road traffic noise; these are Policies 3 to 18. The most relevant to the Project include policy 3 which states the need to “seek a partnership approach with … the Highways Agency … to better understand traffic noise exposure, and to integrate noise management into day to day operations, wherever cost effective and compatible with safety and other needs.” 11.5.9 Policy 7 states that “other organisations should … develop and implement … routeing and related measures which contribute to reducing noise.” 11.5.10 Policy 9 includes the need to “investigate the potential benefits of noise barriers, other noise screening and acoustic modifications to highway structures, where source-related measures would not be effective.” Hertsmere Local Plan 11.5.11 Policy D14: Noisy Development states, “noise-sensitive land uses. Regard will be paid to the cumulative impact of noisy development, the time and nature of the noise and the character of the surrounding area. In particular there is a need to ensure that residential properties, and nature conservation sites, are protected from the impact of undue noise levels. Where planning permission is granted appropriate conditions may be imposed to control the level of noise emitted.” Borough of Broxbourne Local Plan 11.5.12 Policy SUS8 states - (I) New development involving noisy activities should, wherever possible, be sited away from noise sensitive land uses. in cases where location close to a noise sensitive land use is unavoidable, the council will have regard to the following factors in its assessment of the acceptability of the proposal: - The time span over which noise will be generated The nature of the noise generated
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The cumulative impact of any existing noisy development with the proposed development; The character of the adjoining area. (II) Where planning permission is granted, conditions may be imposed to control the level of noise emitted and the time span within which noise is generated. London Borough of Enfield Unitary Development Plan 11.5.13 Policy (ii) EN30: to take into account, when considering planning applications, all matters relating to land, air, noise and water pollution, including: Any possible pollution being caused by any activity within the proposed development; Any opportunities offered by the proposed development for the mitigation of existing pollution problems. Welwyn Hatfield District Plan 11.5.14 Policy R19 states that Proposals will be refused if the development is likely to generate unacceptable noise or vibration for other land uses; or to be affected by unacceptable noise or vibration from other land uses. 11.5.15 Planning permission will be granted where appropriate conditions may be imposed to ensure either: An adequate level of protection against noise or vibration That the level of noise emitted can be controlled. Proposals should be in accordance with the Supplementary Design Guidance. Epping Forest District Local Plan 11.5.16 Policy RP5 states that Epping Forest District Council will not grant planning permission for a development close to existing residential areas, hospitals and Schools where the new development could cause excessive noise. Sensitive development such as Schools which could be subject to either excessive noise from adjoining land uses, traffic or other forms of nuisance except where it is possible to mitigate the adverse effects by the imposition of appropriate conditions. Construction Noise Impacts 11.5.17 The impacts from construction activities are governed by the Control of Pollution Act 1974 and the Environmental Protection Act 1990, although it is noted the Highways Agency and its contractors are exempt from the relevant powers of the Control of Pollution Act. Discretionary powers are available within the Noise Insulation Regulations to provide insulation against construction noise. 11.6 Design, Mitigation and Enhancement Measures 11.6.1 The scheme proposes the use of the hard shoulder as a running lane on the M25 between junctions J23 and J27, with the provision of Emergency Refuge Areas (ERAs) and message sign gantries as necessary. The final locations of the ERAs and gantries had not been confirmed at the time of assessment. Construction Noise Mitigation Measures 11.6.2 The potential impacts of the construction activities can be minimised by use the of noise control measures, as suggested by BS5228 including temporary noise screens and partial enclosures. General principles for the control of noise and vibration during the construction works could include: The use of Best Practicable Means during construction works;
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Switching off plant, equipment and vehicles when they are not in use for longer periods of time; Establishment of agreed site working hours for “normal” construction activities; Establishment of agreed criteria whilst undertaking significantly noisy or vibration-causing operations near to sensitive locations; Programming works such that the requirement for working outside of normal working hours is minimised; Ensuring that all staff and operatives are briefed on the requirement to minimise nuisance from site activities; Use of temporary noise screens or partial enclosures around particularly noisy activities, for example pneumatic breakers used in close proximity to dwellings; Use of silenced compressors, generators and fans at site locations, and Regular plant maintenance. Operational Noise Mitigation and Enhancement Measures 11.6.3 Calculations for this assessment have been undertaken on the latest traffic data and scheme alignments provided. 11.6.4 No operational mitigation measures have been found to be necessary.
11.7 Magnitude of Impacts 11.7.1 Impacts may potentially occur during the operation and construction stages of the scheme. Operational impacts can arise from changes in the alignment of the running lanes and differences in the flow, speed and composition of traffic. Construction impacts will depend on the particular activities being under taken and the time of day that the activities are being undertaken. 11.7.2 This report gives a quantitative assessment of likely noise related impacts from the scheme. The “simple assessment” methodology in the DMRB Volume 11, Section 3, Part 7 has been followed as appropriate. Construction Noise (Temporary) Related Impacts 11.7.3 As design work for the scheme is still in progress, an overview assessment of the construction impacts at noise sensitive receivers has been undertaken for the activities which are likely to be the noisiest to represent a “worst-case”. 11.7.4 Some of the noisiest works will have a comparatively short duration, and therefore these impacts will not be experienced for significant periods of time. Based on data from BS5228, and Atkins previous assessments of other similar schemes, the following construction related impacts are predicted; Daytime Works 11.7.5 In general noise sensitive receptors located closest to any construction activities have the potential to be significantly impacted with increases in noise typically of 5 to 10dB, with smaller increases at properties further back. Appropriate mitigation measures may aid in minimising these impacts, although some residual impact may still be experienced in quieter areas, or areas already screened from the motorway. 11.7.6 In general, significant daytime impacts are not expected for properties more than 80m from the motorway.
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Night-time Works 11.7.7 Night time works may give rise to significant increases in noise of 15 to 20dB for properties closest to the motorway, with smaller increases predicted at properties further back. Appropriate mitigation measures may aid in minimising these impacts, although some residual impact may still be experienced in quieter areas, or areas already screened from the motorway. 11.7.8 In general, significant night-time impacts are not expected for properties more than 200m from the motorway. Road Traffic Noise (Operational) Related Impacts 11.7.9 The operational effects have been subdivided into two parts; Detailed Calculation Area - the results from the noise model report the changes in noise in the detailed calculation area, where changes in traffic flow and motorway running lane alignment are made simultaneously. Qualitative comments are made for the area immediately outside the 600m detailed calculation area. Wider Calculation Area - the results from the wider road network are given, which look at changes in noise arising from changes in traffic flow on routes outside the detailed calculation area. Detailed Calculation Area 11.7.10 The properties within the detailed calculation area have been included within the noise model, by the inclusion of representative calculation points on all properties, and free field noise levels have been calculated at each of these locations. In total, there are 9829 residential properties included in the noise model plus 56 other sensitive receptors. 11.7.11 The noise model results give the impacts taking into account the changes in traffic and the use of the existing hard shoulder as a running lane. 11.3 and 11.4 summarise the results of the noise model. Table 11.3 - Scheme Effects in the Detailed Calculation Area on Scheme Opening (2015) (Short-Term Impacts)
Daytime Change in noise level Number of Number of other dwellings sensitive receptors 0.1 - 0.9 8360 33 Increase in noise 1 - 2.9 258 4 level, LA10, 18h 3 - 4.9 0 0 >=5 0 0
No Change = 0 931 19
0.1 - 0.9 268 0 Decrease in noise 1 - 2.9 12 0 level, LA10, 18h 3 - 4.9 0 0 >=5 0 0
11.7.12 This table identifies that there would be 270 dwellings and 4 other noise sensitive locations experiencing a change greater than 1dB(A) on scheme opening due to increased traffic flow and speed with the scheme. Of these, 258 dwellings are predicted to experience an increase in noise, and 12 are predicted to experience a decrease in noise predominantly because the traffic running on the current hard shoulder wouldbe closer to existing noise barriers, increasing their effectiveness for nearside traffic, resulting in a perceptible decrease in noise level. There are 4
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noise sensitive locations predicted to experience an increase greater than 1dB upon scheme opening. 11.7.13 A total of 9559 dwellings and of 54 other noise sensitive receptors are predicted to experience no change, or a negligible change in noise on scheme opening. 11.7.14 The areas experiencing a minor increase in noise level on opening are listed below, described in order from west to east along the scheme; Isolated properties off Dancers Hill Road and Bentley Heath Lane, south of Potters Bar and M25; Isolated farm property off Stag Hill, southwest of M25 Jct 24; Properties at the eastern side of Potters Bar, north of M25 Isolated properties off The Ridgeway, south of M25, east of Jct 24; Isolated properties off Coopers Lane Road, north of M25, east of Potters Bar; Isolated properties off Cattlegate Road; Clusters of properties north and south of the M25, west of jct 25, including, Oldpark Ride, Bulls Cross Ride, Whitewebbs Lane, Whitewebbs Park and golf course, and Numerous properties in the mixed industrial and residential areas north of M25, east of Holmesdale Tunnel, including Roundhills residential area, Waltham Abbey. Properties in Lodge Lane and Beechfield Walk south of M25, east of Holmesdale Tunnel, Waltham Abbey 11.7.15 A noise contour map showing the change in noise upon opening of the scheme is given in the separate Figure 11.1, (sheets 1 to 8). 11.7.16 Outside the detailed calculation area increases and decreases in noise greater than 1dB(A) are expected at some properties between Junction 24 and Junction 25 and in Waltham Abbey and Potters Bar. Table 11.4 - Scheme Effects in the Detailed Calculation Area by the Design Year (2030) (Long-Term Impacts)
Daytime Night-time Change in noise level Number of Number of other Number of dwellings sensitive receptors dwellings 0.1 - 2.9 4771 38 3035 Increase in noise 3 - 4.9 0 0 0 level, LA10, 18h 5 - 9.9 0 0 0 >=10 0 0 0
No Change = 0 569 3 900
0.1 - 2.9 4488 15 4048 Decrease in noise 3 - 4.9 1 0 0 level, LA10, 18h 5 - 9.9 0 0 0 >=10 0 0 0
11.7.17 Table 11.4 identifies that over the design period no dwellings or other noise sensitive receptors are predicted to experience a significant increase in noise. 11.7.18 A total of 1 dwelling is predicted to experience a minor decrease in noise in the daytime hours.
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11.7.19 A total of 9828 dwellings and 56 other noise sensitive receptors would experience no change, or a negligible change, in noise during daytime hours, over the design period. A total of 7983 dwellings are expected to experience no change, or a negligible change, in noise during night- time hours, over the design period. 11.7.20 Although not a strict requirement of the DMRB simple assessment methodology, Table 11.5 below compares the Do-minimum effects in the future assessment year. This summarises the impacts expected should the scheme not be implemented, and is included for informative purposes. Table 11.5 – Do-Minimum Effects in the Detailed Calculation Area by the Design Year (2030)
Daytime Night-time Change in noise level Number of Number of other Number of dwellings sensitive receptors dwellings 0.1 - 2.9 4251 31 2308 Increase in noise 3 - 4.9 0 0 0 level, LA10, 18h 5 - 9.9 0 0 0 >=10 0 0 0
No Change = 0 590 4 802
0.1 - 2.9 4942 19 4871 Decrease in noise 3 - 4.9 46 2 2 level, LA10, 18h 5 - 9.9 0 0 0 >=10 0 0 0
11.7.21 Table 11.5 shows that if the scheme is not implemented, by the design year, a total of 46 dwellings during the daytime hours, and a total of 2 dwellings during the night-time hours are predicted to experience a significant decrease in noise. These impacts are broadly similar to the results with the scheme in place, and show that on the whole changes in noise by the design year arise from changes in traffic growth and the resurfacing of the motorway that would occur irrespective of whether the scheme were built or not. 11.7.22 Outside the detailed calculation area there would be reductions in noise greater than 3dB(A) at a number of properties primarily due to the resurfacing of the carriageway. 11.7.23 Comparison of Table 11.4 and Table 11.5 suggest that the implementation of scheme has no significant impact within the detailed study area compared to if the scheme were not implemented. 11.7.24 The assessment shows that there may be a small number of properties which would meet the requirements of the Noise Insulation Regulations, but this will require a detailed assessment to confirm. Wider Area Network 11.7.25 The output of the traffic model has been interrogated, and the changes in noise levels on routes assessed. Changes are calculated by looking at the difference in roadside noise level, calculated using the “Basic Noise Level” calculation steps in Calculation of Road Traffic Noise. 11.7.26 The wider area assessment shows that in the opening year no routes are predicted to experience a change in noise exceeding 1dB(A). 11.7.27 The wider area assessment shows that over the design period there are several routes which experience a change in noise greater than 3dB(A), however interrogation of the data shows that all of these predicted increases are primarily due to the growth in traffic which happens in the Do
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Minimum scenario. These predicted impacts are all on roads with relatively low existing traffic flows. Based on the impact of the scheme only in the design year, there are no routes predicted to experience a change in noise exceeding 3dB(A). 11.7.28 It is therefore considered that the implementation of the scheme has no significant impact in the wider area compared to if the scheme were not implemented. 11.8 Significant Effects 11.8.1 The construction phase may give rise to short term significant adverse impacts, particularly if works are required to be undertaken at night. Construction related impacts can be controlled by the use of Best Practicable Means; this is likely to reduce the significance of such impacts. 11.8.2 In summary, on scheme opening, approximately 3% of receptors considered are predicted to experience a minor increase in noise, which would not exist by the design year as a result of resurfacing works. These short term increases in noise are minor in magnitude and the overall effect is not considered to be significant. 11.8.3 Overall, the implementation of the scheme has no significant impact compared to if the scheme were not implemented. 11.9 Identification of Difficulties 11.9.1 Details of the existing noise barriers were limited, and the assessment has been based on the limited information within the 2009 EAR and on-line mapping data sources. 11.9.2 Details of the scheme related ERA and gantry locations and construction methodology have not been available at this stage. Assessment has been based on previous experience, and is not therefore specific to this scheme. It is considered that the calculations undertaken within this assessment are appropriately representative. 11.9.3 Limited extents of OS Landline/Mastermap style data, and Addresspoint style data, was made available for this assessment. The data provided has been incorporated where appropriate. 11.9.4 No OS Landform data was provided, and ground detailing has therefore been taken from the frozen dataset of OS Profile data. It should be noted that OS Profile data also has limited resolution in comparison to landform data, and this limited resolution propagates through to the noise model accordingly. It is considered that this is not of any significance regarding the results presented herein, but commentary is included here for completeness. 11.10 Summary 11.10.1 Calculations for the detailed study area show that on scheme opening, approximately 3% of receptors are predicted to experience a minor change in noise, with the majority of receptors predicted to experience a negligible, or no change, in noise. By the design year, no receptors are expected to experience a perceptible increase in noise. 11.10.2 A number of increases are predicted on routes within the wider area, these increases are predicted to occur both with and without the scheme, and therefore are not direct impacts of the scheme. 11.10.3 The construction works required for the scheme may give rise to short term significant adverse impacts, particularly for works near residential properties, or works taking place at night. Such impacts may be limited by the use of Best Practicable Means. 11.10.4 Overall there would be a slight adverse effect on scheme opening that would reduce to neutral after 15 years.
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12. Effects on All Travellers 12.1 Introduction
12.1.1 The assessment of effects on all travellers has been prepared in accordance with guidance in HA200/08 and Interim Advice Note IAN 125/09 which merges the former chapters for „Pedestrians, Cyclists, Equestrians and Community Effects‟ (DMRB Vol 11, Section 3, Part 9) and „Vehicle Travellers‟ (DMRB Vol 11, Section 3, Part 8) into a combined „Effects on All Travellers‟ chapter.. 12.1.2 The assessment outlined below follows current DMRB guidance in August 2011 and IAN 161/12 which considers this type of scheme, managed motorways. Paragraph 5.4.1 concludes it is unlikely to have any significant impact on NMU (Non Motorised Users) such as pedestrians, cyclists and equestrians. However, IAN 161/12 considers that there is potential for a degree of „urbanisation‟ of the motorway corridor as perceived by vehicle travellers and there is potential stress relief through improved lane discipline, journey time reliability and improved traffic management at incidents. 12.1.3 With this guidance in mind, the effects of the scheme on non-motorised users and communities are scoped out of this EAR and the chapter focuses on the effects on vehicle travellers including travellers‟ views, changes in amenity and driver stress (i.e. frustration, fear of accidents, uncertainty of route and traveller care). 12.2 Study Area 12.2.1 The Study Area for travellers‟ views is represented by the extent of views from the motorway between Junctions 23 to Junction 27 (this is the same as the Landscape Study Area, i.e. the visual envelope as described in Chapter 7 and illustrated in Figures 7.1 and 7.2). There is no defined Study Area for the assessment of travellers‟ stress. 12.3 Baseline Conditions Vehicle Travellers: Baseline Travellers’ Views 12.3.1 The extent of travellers‟ views has been summarised into those views experienced by clockwise travellers and those views experienced by anti-clockwise travellers. In summary, intermittent and open views occur along the majority of the existing motorway route between Junction 23 and 27. Clockwise Travellers’ Views 12.3.2 From Junction 23 to Junction 24 intermittent and open views occur. There are several stretches of embankment which provide open views to the surrounding landscape, where mature vegetation allows. Intermittent views occur where there are short sections of cutting adjacent to Elm Farm and Bentley Heath Farm and on the approach to Junction 24. 12.3.3 From Junction 24 to 25 intermittent views occur due to alternate stretches of embankment followed by short stretches in cutting. 12.3.4 From Junction 25 travellers‟ views are restricted through Holmsdale Tunnel followed by open views at ground level on leaving the Holmsdale Tunnel and through short sections of embankment. There are some intermittent views occurring where noise barriers are located adjacent to built up areas. Views are intermittent at Junction 26 where the motorway goes into cutting for a short stretch. 12.3.5 From Junction 26 views continue to be intermittent as the road travels through short sections of embankment and cutting. This continues, with the exception of Bell Common Tunnel where views
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are restricted, until the approach to Junction 27. There are no views occurring on the approach and through Junction 27 due to the motorway being in cutting and as a result of surrounding built infrastructure associated with Junction 27. Anti-clockwise Travellers’ Views 12.3.6 No view occurs at Junction 27 due to the existing cutting and built infrastructure at this junction. Views are then intermittent of Epping and Copped Hall which is a Listed Building as the road travels along short stretches of embankment and cutting between Junction 27 and 26 (with the exception of Bell Common Tunnel where no views occur). 12.3.7 Views are intermittent at Junction 26 as the motorway goes into a short stretch of cutting. Open and intermittent views then occur to Junction 25, with the exception of Holmsdale Tunnel where views are restricted. On exiting from Holmsdale Tunnel travellers experience views of existing commercial office and warehouse buildings. 12.3.8 Between Junction 25 and 24 intermittent and open views occur as the motorway travels on short stretches of embankment and cutting. 12.3.9 From Junction 24 to 23 intermittent views occur where there are short stretches of cutting and open views occur on short stretches of embankment to the south of Potters Bar. There are some limited views of Potters Bar urban area and the open countryside. 12.3.10 Overall, the sensitivity of the surrounding landscape quality is considered to be high, and further details on the surrounding landscape quality and character are outlined in Chapter 7 of this report. Driver Stress 12.3.11 Existing levels of driver stress on the M25 between Junction 23 and 27 are a combination of: Frustration Fear of accidents Uncertainty of route Traveller Care Frustration 12.3.12 Traffic data for the Base Year of 2004 between Junctions 23 to 27 (clockwise and anti-clockwise) was used to assess the degree of driver stress/frustration under existing conditions. 12.3.13 Analysis of present traffic flows and related stress levels was undertaken in order to capture the stress related to average peak hourly flow rate and average speed Table 12.1 - Base Year 2004 Traffic Data Base Clockwise Anti-Clockwise Year AADT Average Average AADT Average Average Peak Weighted Peak Hourly Weighted Hourly flow/ Speed flow/ lane Speed lane (km/hr) (km/hr) J 23-24 73036.41 1014 95.14 69892.89 971 99.16 J 24-25 67172.63 933 99.41 64090.92 890 101.61 J 25-26 62760.02 872 101.94 62378.43 866 102.43 J 26-27 58454.44 812 102.80 57986.35 805 103.35 Average 908 100 883 102
12.3.14 The average peak hourly flow rate per lane is under 1,200 and the average speed remains over 95 km/hour in all cases. As a result, drivers travelling in both clockwise and anti-clockwise
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directions currently experience low levels of stress (in accordance with the methodology criteria for driver stress set out in Section 12.4, Table 12.6). Fear of Accidents 12.3.15 The fear of accidents can become particularly acute when driving in adverse weather conditions when spray from vehicles reduces visibility. Adverse weather conditions coupled with the limited sight distances caused by the scale and mass of HGVs, makes driving and overtaking more stressful and risky, and therefore increases the fear of accidents. 12.3.16 HGVs currently make up approximately 16% of traffic flow on the motorway between Junction 23 and 27. Uncertainty of Route 12.3.17 Route uncertainty is caused primarily by signage that is inadequate for purposes. 12.3.18 Existing Junctions and destinations are adequately sign-posted for the existing traffic conditions. Traveller Care 12.3.19 The following existing traveller care facilities identified in Table 12.2 are provided within 5 minutes of the motorway, providing a good level of traveller care facilities between Junctions 23 and 27. Table 12.2 - Traveller Care Facilities
Junction Facilities
23 – South Mimms South Mimms Services is a dedicated rest area, which includes full facilities for travellers wishing to take a break from their journey. The service area is part of the Welcome Break chain and includes: a Days Inn Hotel; fast food outlets; restaurant; small retail outlets; cash machine toilets; telephones and a BP petrol station with the capacity to refuel HGVs. Premier Inn Hotel, South Mimms/Potters Bar 24 – Potters Bar Potters Bar Town Centre services, The Royal Chase Hotel Public House (Robin Hood) 25 – Cheshunt/ 4 Petrol Stations Enfield 1 Superstore (including petrol station) 3 Food outlets / restaurants including a small parade of retail outlets Cheshunt Marriot Hotel 2 Public Houses (The Vine & The Pied Bull) 26 – Waltham 1 Petrol station approximately 2km from junction Abbey Mariott Hotel 3 Public Houses (The Volunteer, The Woodbine Inn, The Wake Arms) Junction 26 also includes two lay-bys outside Skillet Hill Farm. The lay-bys include any facilities for travellers but are used as rest areas by HGV and LGV drivers. 27 – M11 No Facilities (M11 interchange only). Interchange
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12.4 Methodology Guidance and Methodology 12.4.1 The assessment of effects on all travellers has been prepared in light of the guidance in HA200/08, IAN125/09 and IAN 161/12: Managed Motorways – All lanes running. This is outlined in Section 12.1. 12.4.2 This Chapter considers the following two sub-topics relating to all travellers: Vehicles Travellers, including: - Travellers‟ Views - Drivers‟ Stress 12.4.3 For the purposes of this assessment these sub-topics have been assessed separately, within the Chapter summary providing an overall significance of effect for all travellers based on the findings of the two separate sub-topic assessments. Vehicle Travellers: Methodology Travellers’ Views 12.4.4 At this stage, a simple level assessment of travellers‟ views has been undertaken based on guidance in DMRB Volume 11, Part 9 Vehicle Travellers. The assessment of the project‟s potential effects upon views from the road is confined to the potential change in the nature and availability of views from the motorway. In accordance with DMRB, aspects to be considered in the „view from the road‟ include: Features within the road corridor i.e. lighting and gantries; Types of scenery or landscape character visible from the road; Quality of the landscape visible from the road; Extent to which travellers may be able to view the scene; and Features of particular interest or prominence in the view. 12.4.5 The sensitivity or the quality of the landscape character in the views from the motorway was assessed using the same criteria as for Chapter 7: Landscape. 12.4.6 The extent of views from the motorway has been assessed using the criteria and descriptions outlined in DMRB Volume 11, Part 9. The categories used in assessing traveller‟s ability to see from the motorway are: No view – road in deep cutting or contained by earth bunds, environmental barriers or adjacent structures. Restricted view – frequent cuttings or structures blocking the view. Intermittent view – road generally at ground level but with shallow cuttings or barriers at intervals. Open view – view extending over many miles, or only restricted by existing landscape features. 12.4.7 The assessment of the Project‟s potential effect on travellers‟ views was confined to the potential change in the nature and availability of views from the motorway. 12.4.8 For travellers‟ views relative levels of value (sensitivity) was not assigned to the receptors. For the purposes of this assessment all vehicle travellers‟ on the motorway are considered to have the same sensitivity to views from the road.
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12.4.9 The magnitude of impact on travellers‟ views was assessed using a simple three-point scale as shown in Table 12.3. Table 12.3 - Travellers’ Views – Magnitude of Impact Magnitude Description of Impact Major Loss of resource and/or quality and integrity; severe damage to key characteristics, features or elements (Adverse). Large scale or major improvement of resource quality; extensive restoration or enhancement; major improvement of attribute quality (Beneficial). Moderate Significant impact on the resource, but not adversely affecting the integrity; Partial loss of/damage to key characteristics, features or elements (Adverse). Benefit to, or addition of, key characteristics, features or elements; improvement of attribute quality (Beneficial). Minor Some measurable change in attributes quality or vulnerability; minor loss of, or alteration to, one (maybe more) key characteristics, features or elements (Adverse). Minor benefit to, or addition of, one (maybe more) key characteristics, features or elements; some beneficial impact on attribute or a reduced risk of negative impact occurring (Beneficial). Negligible Very minor loss or detrimental alteration to one or more characteristics, features or elements (Adverse). Very minor benefit to or positive addition of one or more characteristics, features or elements (Beneficial). No Change No loss or alteration of characteristics, features or elements; no observable impact in either direction.
12.4.10 There are no agreed significance criteria within DMRB relating to the effect on vehicle travellers and reference has been made to IAN125/09 and Section 2 of DMRB Volume 11. An approach for identifying the significance of the effects has been identified using the criteria and impact scores as suggested in HA 205/08 and shown in Table 12.4. Table 12.4 - Significance Descriptors Significance Typical Descriptors of Effect Category Large These beneficial or adverse effects are considered to be very important considerations and are likely to be material in the decision-making process. Moderate These beneficial or adverse effects may be important, but are not likely to be key decision-making factors. The cumulative effects of such factors may influence decision-making if they lead to an increase in the overall adverse effect on a particular resource or receptor. Slight These beneficial or adverse effects may be raised as local factors. They are unlikely to be critical in the decision-making process, but are important in enhancing the subsequent design of the project. Neutral No effects or those that are beneath levels of perception, within normal bounds of variation or within the margin of forecasting error.
Drivers’ Stress 12.4.11 The assessment of drivers‟ stress was based on four main factors: Frustration; Fear of Accidents; Uncertainty of Route; and Traveller Care.
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12.4.12 For the purposes of this assessment relative levels of value (sensitivity) have not been assigned to the receptors (vehicle travellers). All drivers on the motorway are considered to have the same sensitivity in relation to drivers‟ stress. Frustration 12.4.13 The main factors contributing towards driver frustration along the motorway relate to the existing carrying capacity of the carriageway. Vehicles are forced to reduce speed considerably during peak traffic flows. Congestion can become acute when an accident or breakdown closes one or more lane. 12.4.14 As an indicator of drivers‟ stress/frustration, DMRB tabulates the relationship between average peak hourly flow per lane and average journey speed, in order to describe the magnitude of drivers‟ stress on a three point scale: low; moderate and high: Table 12.5 - Driver Stress/Frustration Magnitude of Impact
Average peak hourly flow per lane, in Average Journey Speed km/hr flow units/hr Under 75 75-95 Over 95
Under 1,200 High Moderate Low
1,200-1,600 High Moderate Moderate
Over 1,600 High High High
12.4.15 Data on AADT flows and traffic speeds from the SATURN traffic model were used to assess the degree of drivers‟ stress as a result of the Project. 12.4.16 In accordance with DMRB, an assessment of driver stress is made for the worst year in the first fifteen years after opening (the Design Year). The following are used for the assessment: 2013 – 2014 – start of construction; 2014 – 2015 – the expected opening years; and 2029 – 2030 taken as future years. Fear of Accidents 12.4.17 The fear of accidents can become particularly acute when driving in adverse weather conditions when spray from vehicles reduces visibility. Adverse weather conditions coupled with the limited sight distances caused by the scale and mass of HGVs, makes driving and overtaking more stressful and risky, and therefore increases the fear of accidents. 12.4.18 The assessment reviews the average % of HGVs on the motorway between Junction 23 and 27 for the construction of the route, the expected opening years and the future years. Uncertainty of Route 12.4.19 Route uncertainty is caused primarily by signing that is inadequate for purpose. This assessment considers the adequacy of existing signage and proposed signage as part of the Project. Traveller Care 12.4.20 The assessment of drivers‟ stress also considers traveller care and whether sufficient traveller care facilities are provided in close proximity to the Project route. Drivers’ Stress Overall Significance of Effect 12.4.21 A judgement as to the overall significance of effect for drivers‟ stress is then made in accordance with Table 12.6.
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Table 12.6 - Drivers’ Stress Significance of Effects
Significance of effect Description
Very large beneficial or adverse Where there would be a very major increase/reduction in driver stress resulting from the Project compared to the do minimum
Large beneficial or adverse Where there is a major increase/reduction in driver stress resulting from the Project compared to the do minimum
Moderate beneficial or adverse Where there is a moderate increase/reduction in driver stress resulting from the Project compared to the do minimum
Slight beneficial or adverse Where there is a minor increase/reduction in driver stress resulting from the Project compared to the start year and future years.
Neutral Where no effects on driver stress are anticipated from the Project, or where the beneficial and adverse effects are considered balanced. 12.5 Value (Sensitivity) of Resource Vehicle Travellers: Value of Resource 12.5.1 For the purposes of this assessment, all vehicle travellers‟ on the motorway are considered to have the same sensitivity to change (including views from the road and driver stress). 12.6 Regulatory/Policy Framework National Policy National Planning Policy Framework, Adopted March 2012 12.6.1 On 27th March 2012 the government published the National Planning Policy Framework. The National Planning Policy Framework (NPPF) is a key part of Government reforms to make the planning system less complex and more accessible, to protect the environment and to promote sustainable growth. The NPPF now adopted, replaces Planning Policy Guidance Notes and Planning Policy Statements, as outlined in Annex 3 of the NPPF. 12.6.2 The NPPF This Framework does not contain specific policies for nationally significant infrastructure projects for which particular considerations apply. These are determined in accordance with the decision-making framework set out in the Planning Act 2008 and relevant national policy statements for major infrastructure, as well as any other matters that are considered both important and relevant (which may include the National Planning Policy Framework). 12.6.3 National policy statements form part of the overall framework of national planning policy, and are a material consideration in decisions on planning applications. 12.6.4 At the heart of the National Planning Policy Framework is a presumption in favour of sustainable development, which should be seen as a golden thread running through both plan-making and decision-taking. 12.6.5 For decision-taking this means approving development proposals that accord with the development plan without delay; and where the development plan is absent, silent or relevant policies are out-of-date, the presumption is in favour of granting planning permission unless:
any adverse impacts of doing so would significantly and demonstrably outweigh the benefits, when assessed against the policies in this Framework taken as a whole; or specific policies in this Framework indicate development should be restricted.
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12.6.6 In terms of transport infrastructure, the national policy driver is to promote sustainable transport modes - any efficient, safe and accessible means of transport with overall low impact on the environment, including walking and cycling, low and ultra low emission vehicles, car sharing and public transport. Whilst this project is essentially a managed motorway, with the emphasis on vehicular transport, increasing capacity through using hard shoulder running predominantely in the existing highway boundary, can be considered a sustainable use and management of existing highway networks. Regional Policy 12.6.7 Under Part 1 of the Planning and Compulsory Purchase Act (2004) Regional Spatial Strategies have been prepared throughout England by the relevant regional planning body. The Government has committed to revoking the Regional Spatial Strategies under the provisions of the Localism Act (2011) (Clause 89 and Schedule 8). In July 2010 the UK Government formally revoked Regional Spatial Strategies through the Local Democracy Economic Development and Construction Act 2009. However, a high court ruling determined that the Regional Spatial Strategies could not be abolished through this legislation and Regional Spatial Strategies have been reinstated for the time being. 12.6.8 The Localism Bill that includes plans to abolish Regional Spatial Strategies has now been enacted, so the policies contained within the RSSs are no longer a material consideration. Spatial Development Strategy The London Spatial Development Strategy 2011 12.6.9 The London Plan includes policy 6.11 (Smoothing Traffic Flow and Tackling Congestion and Policy 6.12 (Road Network capacity). Policy 6.11 says that DPD‟s and LIPS should take a coordinated approach to smoothing traffic flow and congestion. Policy 6.12 states that “The Mayor supports the need for limited improvements to London‟s road network, whether in improving or extending existing capacity, or providing new links, to address clearly identified significant strategic or local needs.” Local Policy Hertsmere Borough Council Local Plan 12.6.10 Hertsmere Borough Local Plan (Hertsmere Borough Council, 2003) includes Policy M14 – South Mimms (Bignells Corner) Special Policy Area, which states that South Mimms is in the green belt and planning permission will only be granted for facilities relating to the movement of people and goods on the motorway i.e. works required on the M25. Welwyn Hatfield District Plan 12.6.11 Welwyn Hatfield District Plan (Welwyn Hatfield Borough Council, 2005) there are no policies relevant to this scheme. Borough of Broxbourne Local Plan 12.6.12 Borough of Broxbourne Local Plan (Borough of Broxbourne, 2005) includes Policy T3: Transport and New Development which states: “(I) All development proposals including re-development and changes of use will be considered against the amount, type and timing of transport movements likely to be generated and the effect on the local highway, public transport systems, footpaths, bridleways, cycle routes and the environment. (II) Development will not be permitted where:…
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(b) the safety of road users, including cyclists, powered two-wheelers and pedestrians, is compromised…” 12.6.13 Borough of Broxbourne Submission Core Strategy December 2010 included Policy CS9; Infrastructure which aims to bring forward infrastructure that supports housing employment, retail and leisure in addition to working with the HA relating to the capacity of the M25 and A10. The Enfield Plan Core Strategy 12.6.14 The Enfield Plan Core Strategy 2010 includes Policy 24 which seeks to deliver improvements to the road network with partners. Epping Forest District Plan 12.6.15 Epping Forest District Plan (Epping Forest District Council, 2008) includes Policy ST7: New Roads and Extensions or Improvements to Existing Roads which states that: “The Council expects schemes for new roads or for extensions and improvements to existing roads to satisfy the following criteria:… (iii) minimal disruption to, or realignment of, the rights of way network;...” 12.7 Design, Mitigation and Enhancement Measures Vehicle Travellers: Design, Mitigation and Enhancement Measures Construction 12.7.1 Traffic management would be in place during construction and restrictions on the existing motorway would be minimised. Three lanes would be maintained during peak times but access to the hard shoulder may be periodically restricted. A 24-hour recovery service would be provided over the complete length of the traffic management area. Design 12.7.2 Loss of mature vegetation would be minimised through good construction practices, which would assist in protecting existing travellers‟ views. 12.7.3 The following aspects of the Project would assist in helping to reduce driver stress: The Project would satisfy current design standards; New signal and ADS gantry and cantilever signals would manage greater traffic flows; and Use of the hard shoulder during peak times would manage greater traffic flows. 12.7.4 No new or upgraded traveller care facilities are included as part of the Project. 12.8 Magnitude of Impacts (Change) Vehicle Travellers: Magnitude of Impacts Travellers’ Views 12.8.1 Impacts considered by the assessment include: The extent to which travellers view would change; and Change in features of particular interest or prominence in the view. 12.8.2 There will be additional gantry and cantilever signs and short stretches of widening on the approaches to the Holmsdale Tunnel and Bell Common Tunnel. Overall however, the Project will retain the majority of existing open and intermittent views along the route. The Project will therefore result in a slight adverse effect on overall views from the road.
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Drivers’ Stress Frustration 12.8.3 Driver stress/frustration has been calculated for Design Year (2030) which is forecast to have the highest traffic flows within fifteen years after the Project opens. 12.8.4 Tables 12.4 and 12.5 illustrate the average peak hourly flow per lane and average weighted speed for the year 2030 without the Project in place (Do Minimum) and the year 2030 with the Project in place (Do Something) scenarios.
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Table 12.6 - 2030 Do Minimum Traffic Data
Base Clockwise Anti-Clockwise Year AADT Average Average AADT Average Average Peak Hourly Weighted Peak Weighted flow/per lane Speed Hourly Speed (km/hr) (km/hr) flow/per lane
J 23-24 87464 1215 84.28 85346 1185 87.29
J 24-25 79761 1108 89.83 77068 1070 93.79
J 25-26 74559 1036 94.37 74176 1030 93.33
J 26-27 71135 988 96.12 73737 1024 95.47
Average 1087 91 1078 92
Table 12.7 - 2030 Do Something Traffic Data
Base Year Clockwise Anti-Clockwise
AADT Average Average AADT Average Average Peak Weighted Peak Weighted Hourly Speed Hourly Speed (km/hr) flow/per (km/hr) flow/per lane lane
J 23-24 101189 1054 84.49 96576 1006 87.51
J 24-25 94285 982 88.69 90043 938 91.44
J 25-26 87797 915 91.11 86759 904 93.06
J 26-27 82148 856 93.28 83740 872 94.08
Average 952 89 930 92
12.8.5 The average peak hourly flow with the Project (Do Something) in 2030 is 941 vehicles per lane. The average journey speed is predicted to be on average 90km/hr resulting in moderate levels of driver stress, with reference to Table 12.5 in assessing magnitude of change 12.8.6 In comparison, the predicted average peak hourly flow in 2030 without the Project (Do Minimum) would be slightly higher, on average 1,082 vehicles per lane, with an average speed of 92km/h. . 12.8.7 The traffic data forecasts show that traffic volumes are expected to increase in 2030, compared to existing traffic flows shown in Table 12.4,, either with or without the Project in place. Traffic flows averages are predicted to be slightly higher on average in 2030 without the Project in place therefore, with the project, driver stress levels are predicted to be lower than do minimum scenario resulting in slight beneficial effects Fear of Accidents 12.8.8 The percentage of HGVs on the motorway is predicted to be 15% in 2030 without the Project (Do Minimum) and to be a percentage lower, at 14%, in 2030 with the Project in place (Do Something). This is similar to the existing level of HGVs on the road (Base Year 2004: 16% HGVs). Therefore the overall fear of accidents (based on HGV mass) remains relatively constant with or without the Project in place.
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Route Uncertainty 12.8.9 The Project would incorporate improved ADS, gantry and cantilever message signs which would help alleviate uncertainty of the route and improve driver comfort compared to the Do Minimum resulting in slight beneficial effects. Traveller Care 12.8.10 No additional facilities are proposed as part of the Project. A good level of facilities for traveller care are already provided in close proximity to the Project (refer to Table 12.2). The overall traveller care facilities remain the same with or without the project although improved signage may prompt drivers to utilise the existing South Mimms MSA and in accessing local towns and villages such as Cheshunt, Potters Bar and Enfield. 12.9 Significant Effects Vehicle Travellers: Significant Effects Travellers’ Views 12.9.1 There will be additional gantry and cantilever signs which will be visible in views from the road. However, the Project will retain all existing open and intermittent views along the route. The Project will result in a slight deterioration in views from the road, resulting in slight adverse effects on travellers‟ views. During construction there may also be short term adverse effects to a slight degree. Drivers’ Stress 12.9.2 Whilst the traffic data forecasts show that traffic volumes (AADT) are expected to increase in 2030, compared to existing conditions, traffic flow averages are predicted to be slightly higher on average in 2030 with the project in place due to additional lane capacity, and as such, driver stress levels are predicted to be lower than do minimum scenario resulting in slight beneficial effects. In addition, the Project would incorporate improved ADS, together with gantry and cantilever message signs which would help alleviate uncertainty of route and improve driver comfort. As a result, the overall impact on driver stress resulting from the Project will be Slight Beneficial. Significance of Effects on Plans and Policies 12.9.3 The project would not significantly hinder any of the objectives of national, regional or local planning policies as described. The project would achieve the objectives of Policy 6.11 of the London Plan which aims to smooth traffic flow and tackle congestion, Policy 6.12 on the road capacity network as well as Policy T6 of the South East Plan. Overall, the project will improve journey time reliability, ease congestion and reduce traveller stress and would comply with the objectives that relate to improvements to the M25. As a result, the project would generally have a beneficial effect on national, regional and local transport policies. 12.9.4 The table below illustrates the significant effects on the plans and policies. Table 12.8 - Significance of Effects Neutral Effect Beneficial T3 (Broxbourne) NPPF Hertsmere Local Plan Policy, M14 London Plan 3c.16, Policy 6.11 and 6.12. Broxborne Core Strategy CS9. Enfield Core Strategy, Policy 24 Epping Forest Local Plan, ST7
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12.10 Indication of Any Difficulties Encountered 12.10.1 No difficulties have been encountered whilst undertaking this assessment. 12.11 Summary 12.11.1 The overall assessment of permanent effects on Vehicle Travellers in the long term, taking in account traveller views and driver stress outlined in this chapter, is considered to be neutral.
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13. Community and Private Assets 13.1 Guidance 13.1.1 The scope of assessment for community and private assets has been prepared in light of the guidance provided in HA200/08 and IAN111/09. This sees the original chapter for „Land Use‟ (Vol 11, Section 3, Part 6 and the Community Effects‟ section of Vol 11, Section 3, Part 8 merging into and combined chapter titled „Community and Private Assets‟. The former „Impact of Road Schemes on Policies and Plans‟ (Vol 11, Section 3, Part 12) chapter has been absorbed into each specialist chapter. 13.1.2 This chapter therefore sets out the scope for assessing the Project against national, regional and local planning and transport policies, objectives and guidance in order to consider to what extent the Project integrates with the current and emerging land use and transport planning policy framework for the study area. The assessment of how the Project integrates with local planning policies is set out within the individual topic chapters. Land Use and Community Effects are no longer part of the assessment as all of the proposed development is to be undertaken within the highway boundary and therefore no longer required. 13.2 Study Area 13.2.1 There are two dimensions to the Study Area. Firstly there is the consideration of strategic policies and objectives at a national and regional level, which do not relate to a specific Study Area boundary. Secondly, there are location specific policies and proposals that the Project may have an impact on, either directly or indirectly. 13.3 Methodology 13.3.1 As stated above, in accordance with the updated Volume 11 Section1 HA200/08 there is no longer a separate chapter on „Impact of Road Schemes on Policies and Plans‟. Policies and plans are now assessed under the relevant topic chapter headings. 13.3.2 The methodologies used in this report are derived from the DMRB Volume 11, Section 3, Part 12: Policies and Plans. Assessment criteria have been supplemented by the methodology provided in IAN 161/12. 13.3.3 Paragraph 1.2 in Volume 11, Section 3, Part 12 of the DMRB states that a Stage 3 assessment requires an assessment of the „wider context of national, regional, strategic and detailed planning policies‟. Paragraph 1.3 confirms that the purpose of the assessment is to assess how the achievement of policy objectives would be facilitated, hindered or be unaffected by the Project. 13.3.4 Each individual policy was reviewed at a National and Regional level in order to ascertain if the data currently being used was the most up to date and correct. Several of the policies had expired and were removed, whereas others were replaced with newer and alternative policies with their objectives updated. The National Planning Policy Framework (NPPF) adopted in March 2012, (which has replaced Planning Policy Guidance Notes and Planning Policy Statements) and the Development Plan has been examined. A schedule of relevant policies and plans has been prepared. 13.3.5 The assessment uses the criteria outlined in Table 13.1 in order to show how policy objectives would be facilitated or hindered by the Scheme. Using professional judgement, significance assessment criteria have been devised to predict the significance of effects arising from the Project. The significance criteria have been created to comply with requirements set out in DMRB Volume 11 Section 3, Part 12
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Table 13.1 - Planning Assessment Criteria
Assessment Contribution to Achievement of Policy Objectives Score
Beneficial The project contributes to, or is consistent with, the policy.
Neutral A change that is neither positive nor negative in terms of the objectives of planning policies.
Adverse The project hinders, or is inconsistent with, the policy.
13.3.6 This assessment makes clear the degree to which policy objectives would be facilitated or hindered by the Project, and consequently, the significance of the effects. This includes consideration of the following: Weighting - the statutory status of the policy document, i.e. whether the development plan has been adopted or which statutory procedures stage it has reached Context of the Impacts - location specific policies will be given greater weight than non- specific policies Permanence - whether the effect of the Project upon policy objectives will be temporary (e.g. increased noise levels or reduced amenity) or permanent (i.e. the result of a more permanent change to the baseline environment, e.g. land take), or may persist for the foreseeable future (e.g. increased noise levels from operations or activities) Temporary impacts may include: - accordance or conflict with planning policy or designations protecting a specific resource - loss of land or buildings allocated for a specified use within emerging or adopted development plans Permanent impacts may include: - accordance or conflict with planning policy or designations protecting a specific resource - loss of land or buildings allocated for a specific use within emerging or adopted development plans Direct/Indirect Impacts - whether these are anticipated to be direct impacts that arise from the activities that form an integral part of the Project (e.g. new construction features); or indirect/secondary impacts that arise from the activities that do not explicitly form part of the Project. Regulatory Framework 13.3.7 In establishing the planning policy framework, a number of documents was consulted, which are detailed Table 13.2 below: National Policy 13.3.8 National Transport Policy relating to hard shoulder running schemes has been developed from the Integrated Transport White Paper - A New Deal for Transport: Better for Everyone (1998) and the relatively recent Roads – Delivering Choice and Reliability (2008). These documents give priority to improving the maintenance and management of existing roads before building new ones; and seek to improve journey time reliability and safety whilst having regard for the environment. 13.3.9 The HA takes its lead from these documents and subsequent Ministerial announcements in progressing projects through the Project Control Framework (www.highways.gov.uk/roads/19638.aspx). The HA also have Strategic Plans relating to Environment, Accessibility, Safety and Integration. 13.3.10 The National Planning Policy Framework (NPPF) was published in March 2012. It is a key part of the coalition Government’s reforms which aim to make the planning system less complex and
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more accessible and to promote sustainable growth. It consolidates all policy statements, circulars and guidance documents into a single, simpler Framework. Now adopted, the NPPF replaces all the existing PPSs and PPGs, as well as a number of Circulars. 13.3.11 At the heart of the National Planning Policy Framework is the presumption in favour of sustainable development, and states that the Government is committed to ensuring that the planning system does everything it can to support sustainable growth (paragraph 13). Paragraph 14 states that “At the heart of the planning system is a presumption in favour of sustainable development, which should be seen as golden thread running through ....decision making” (paragraph 14, page 4). 13.3.12 The NPPF sets out 12 core planning principles and 13 policies. According to the core principles planning should: Be kept up to date, practical and based on communities‟ participation, joint working, and co- operation, addressing larger than local issues. Be a creative exercise enhancing places. Be proactive and support sustainable economic development, delivering the homes, business, industrial units and infrastructure. Specifically, plans should set out a clear strategy for allocating sufficient land for development based on the local needs. Always seek to secure high quality design and a good standard of amenity. Recognise diverse roles and character of different areas, both rural and urban and protect the Green Belts around main urban areas. Support the transition to a low carbon future in a changing climate and with a diminishing natural resource base. Contribute to conserving and enhancing the natural environment and reducing pollution. Land of lesser environmental value should be preferred for allocation. Reuse previously developed land, if it is not of high environmental value. Promote mixed use developments, and recognise and encourage multiple benefits from land use. For example, open land can perform such diverse functions as wildlife support, recreation, flood risk mitigation, carbon storage or food production. Conserve heritage assets. Growth patterns should tie in with opportunities for sustainable transport, e.g. public transport, walking and cycling. Aim to improve health, social and cultural wellbeing for all, and deliver sufficient community and cultural facilities and services. 13.3.13 Policy 4 seeks to promote sustainable transport modes. Para 29 states that “transport policies have an important role to play in facilitating sustainable development but also in contributing to wider sustainability and health objectives. . It is recognised that sustainable transport solutions may vary from place to place, however, the overall aim should be to reduce greenhouse gas emissions and congestion” (para 30) 13.3.14 Local authorities should work with neighbouring authorities and transport providers to develop strategies for the provision of viable infrastructure (para 31). All developments that generate significant amounts of movement should be supported by a Transport Statement or Transport Assessment (para 32). The following should inform the preparation of plans and decision-making: the opportunities for sustainable transport modes have been taken up depending on the nature and location of the site, to reduce the need for major transport infrastructure; safe and suitable access to the site can be achieved for all people; and
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improvements can be undertaken within the transport network that cost effectively limits the significant impacts of the development. Development should only be prevented or refused on transport grounds where the residual cumulative impacts of development are severe.‟ 13.3.15 Whilst this project is essentially a managed motorway, with the emphasis on vehicular transport, increasing capacity through using hard shoulder running predominantly in the existing highway boundary can be considered a sustainable use and management of existing highway networks. Regional Planning Guidance 13.3.16 The Government has committed to revoking the Regional Spatial Strategies under the provisions of the Localism Bill (2011) (Clause 89 and Schedule 8). Now that the Localism Bill has received Royal Assent and has become the Localism Act, 2012, Regional Spatial Strategies no longer form part of the development plan for the purposes of determining planning applications. 13.4 Assessment of Effects 13.4.1 An assessment of the compliance of the Project with national and regional planning policy is presented in the following Planning Impact Tables. Table 13.2 displays the Policies and Objectives that have been assessed against the Project.
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Table 13.2 - National and Regional Planning Policy
Policy Objectives Significance of Comment Effect
DEPARTMENT FOR TRANSPORT
Integrated Transport White Paper – A The White Paper states that “top priority (will be Beneficial The Project involves the improvement of an existing transport New Deal for Transport: Better for given) to improving the maintenance and corridor to increase capacity, improve journey reliability and Everyone,1998 management of existing roads before building new safety on the M25 through management. Traffic management ones” (Para 3.123) by “investing in network control, involves the inclusion of hard shoulder running for use during traffic management and in minor improvements” peak periods in order to relieve congestion. which “promote carefully targeted capacity improvements to address existing congestion”
Transport 2010: The 10 Year Plan, Outlines transport investment to be made over the Neutral The Project will comply with the objectives of this plan, 2000 10 year period between 2000 and 2010. It aims to improving journey time reliability and easing bottlenecks. tackle congestion and pollution by improving all However, it does not increase transport choice as the Project types of transport in ways that increase choice. relates solely to vehicle-based transport.
Tomorrow‟s Roads Safer For Everyone, Outlines safety objectives for designing, building, Beneficial As set out in the Project Objectives, the Project involves the 2000 operating and maintaining trunk and local roads. improvement of an existing transport corridor to increase capacity, improve journey reliability and safety on the M25 through management. The Project will contribute to improved safety over the long term.
The Future of Transport - White Paper Looks at the factors that will shape travel and Beneficial The Project will allow for the required additional vehicle CM 6234 , 2004 transport over the next thirty years and sets out capacity, but does not involve any demand management. how the Government will respond to the increasing The Project would have a slight adverse effect upon demand for travel, maximising the benefits of biodiversity, landscape and visual amenity. Air quality would transport while minimising the negative effects on deteriorate with the Project. However, the Project maximises people and the environment. the potential of the existing M25 corridor by using the hard shoulder to increase capacity.
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Policy Objectives Significance of Comment Effect
Towards a Sustainable Transport Government's commitment to a transport policy Beneficial The Project aims to improve journey times by easing System which delivers economic growth and lower carbon congestion volumes on the existing road network. This Supporting Economic Growth in a Low emissions. It summarises the policy and supports effective journey times and the reduced construction/ Carbon World, 2007 investment plans over the period to 2014; and improvement costs on the existing road network. The Project describes how the Government will implement a results in a decrease in carbon emissions by the 2030 design new approach to strategic transport planning for year thereby helping achievement of this policy. the period 2014-19 and beyond.
Roads – Delivering Choice and This paper sets out an intention to use managed Beneficial The Project will be a managed motorway which is designed to Reliability motorways to achieve the capacity benefits of achieve the capacity, journey reliability and safety benefits of a 2008 motorway widening with lower costs. widening scheme.
Britain‟s Transport Infrastructure – This paper discusses managed motorways and Beneficial The Project will be a managed motorway which is designed to Motorways and Major Trunk Roads sets out areas which are suitable for this scheme. achieve the capacity, journey reliability and safety benefits of a 2009 The M25 Widening Schemes are discussed with widening scheme. the potential to amend them to managed motorways schemes with an average saving of 40% on capital costs, while for particular schemes savings could be almost 60%. HIGHWAYS AGENCY
Highways Agency Biodiversity Action Aims to minimise the impact of the trunk road Adverse In terms of biodiversity, the ecological assessment concludes Plan (HABAP) network on the natural and built environment, and slight adverse effects on ecology features as a result of loss This is currently being reviewed conserve habitat and species on motorway verges. and severance.
Encouraging Sustainable Travel - Seeks to promote accessibility to everyday Neutral The Project would not contribute to improving accessibility for Highways Agency Strategic Plan for facilities for all, especially those without a car. The those without a car. However, it is located within an existing Accessibility impact of the trunk road network on other modes of route corridor, therefore does not interfere with other non- transport is recognised. vehicular modes of transport. No Public Rights of Way are likely to be affected during construction or operation.
Working in Partnership: - Highways Seeks to widen the choice of transport available by Neutral The Project is designed to increase capacity on an existing Agency Strategic Plan for Integration facilitating interchanges between roads and public route corridor; however it would not widen the choice of transport, walking or cycling. transport available.
Making the Network Safe: Highways States the Highway Agency‟s commitment to Beneficial The Project would improve journey time reliability and Agency Strategic Plan for Safety contributing to the Government‟s targets for certainty. Safety would be improved through inclusion of speed reducing road deaths and casualties, and identifies cameras/CCTV, variable messaging signs and emergency actions to help achieve casualty reductions. refuge areas.
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Policy Objectives Significance of Comment Effect
Better Value from Busy Roads: Seeks to reduce overall travel costs, increase Beneficial The Project would improve journey time reliability and Highways Agency Economic Strategic journey time reliability and minimise construction certainty. The incorporation of the hard shoulder running would Plan and maintenance costs. automatically increase journey time reliability. The construction costs would be lower when compared to widening.
Highways Agency – Environment This is intended to mitigate the negative effects of Adverse This is realising where there are detrimental impacts on the Strategy 2010 – 2015 (2011) our roads. It is supported by „Managing our scheme and identifying ways in which these can be mitigated Approach to Environmental Performance‟ against. The project will result in residual slight adverse effects on ecology and landscape which will be mitigated where possible.
Highways Agency Strategic Plan 2010 - This is a plan to meet the goals by improving road Beneficial The scheme would meet the goal of improving 2015 communications for the road user; to deliver communications to the road users through improved signage, schemes on time and in budget; to make the right gantries and variable messaging signs reducing route solutions; meet safety and; be innovative. uncertainty and making the driver more aware of potential delays and congestion.
DEFRA
Working with the Grain of Nature: A Seeks to ensure biodiversity considerations Adverse In terms of biodiversity, the project would have a slight adverse Biodiversity Strategy for England become embedded in public policy and sets out a effect through loss of verge habitats. These habitats are no 2002 programme for the next five years to make the greater than „lower‟ in value. changes necessary to conserve, enhance and work with ecosystems.
The Air Quality Strategy for England, The strategy sets out a way forward for work and Neutral The air quality assessments indicate a negligible effect on air Scotland, Wales and Northern Ireland planning on air quality issues, the air quality quality, with no exceedances of the EU Limit Values for NO2 2007 standards and objectives to be achieved, and PM10 with the mitigated scheme. The assessment introduces a new policy framework for tackling fine concludes that there would be no significant effects on air particles and identifies potential new national quality. policy measures which modelling indicates could give further health benefits and move closer towards meeting the Strategy‟s objectives.
The Natural Choice (White Paper) 2011 This aims to protect and improve our natural Adverse In terms of biodiversity, the project would have a slight adverse environment, looking towards a green economy effect through loss of verge habitats. These habitats are no and getting people to reconnect to nature. greater than „lower‟ in value. However the scheme does not restrict access to nature. COMMUNITIES AND LOCAL GOVERNMENT National Planning Policy Framework, At the heart of the National Planning Policy Beneficial In terms of transport infrastructure, the national policy driver is March 2012 Overview Framework is a presumption in favour of to promote sustainable transport modes - any efficient, safe
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Policy Objectives Significance of Comment Effect sustainable development, which should be seen and accessible means of transport with overall low impact on as a golden thread running through both plan- the environment, including walking and cycling, low and ultra making and decision-taking. low emission vehicles, car sharing and public transport. Whilst this project is essentially a managed motorway, with the emphasis on vehicular transport, increasing capacity through using hard shoulder running predominantly in the existing highway boundary can be considered a sustainable use and management of existing highway networks.
In addition, the Project would deliver public benefits in terms of reduced congestion and benefits to the environment by using a managed motorway scheme rather than constructing an additional permanent lane and thus widening the carriageway.
NPPF Building a strong, competitive economy - Beneficial The Project aims to improve journey times by easing „Achieving Sustainable Development‟ emphasises the government‟s commitment to congestion volumes on the existing road network. This Objective 1 securing economic growth in order to create jobs supports effective journey times and the reduced construction/ and prosperity. Para 19 states that significant improvement cost on the existing road network and may have weight should be placed on the need to support a beneficial influence on supporting economic growth. economic growth through the planning system. NPPF Ensuring the vitality of town centres. Beneficial The Project aims to improve journey times by easing „Achieving Sustainable Development‟ congestion volumes on the existing road network and Objective 2 improving accessibility which may have an indirect beneficial influence on supporting town centres. NPPF Supporting a prosperous rural economy. Neutral Not applicable to this project. „Achieving Sustainable Development‟ Objective 3
NPPF Promoting sustainable transport - Para 29 states Beneficial The aim of the Project will be to reduce congestion, improve „Achieving Sustainable Development‟ that transport policies have an important role to access and reliability to the M25. The Project will make Objective 4 play in facilitating sustainable development but improved use of an existing transport corridor which is a more also in contributing to wider sustainability and sustainable option that new build which outweighs the slight health objectives. It is recognised that sustainable adverse effects predicted for ecology, local landscape and transport solutions may vary from place to place, visual amenity. however, the overall aim should be to reduce greenhouse gas emissions and congestion (para 30). NPPF Supporting high quality communications Neutral Not applicable to this project. „Achieving Sustainable Development‟ infrastructure. Objective 5
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Policy Objectives Significance of Comment Effect
NPPF Delivering a wide choice of high quality homes. Neutral Not applicable to this project. „Achieving Sustainable Development‟ Objective 6
NPPF Requiring good design - The policy states that Neutral The Project will lead to a very minor intensification of the „Achieving Sustainable Development‟ good design is indivisible from good planning. presence and appearance of the carriageway with additional Objective 7 High quality design should be sought for individual signage and lighting which may have an urbanising effect, buildings, public and private spaces and wider although not significant. area development schemes (para 57). NPPF Promoting healthy communities. Neutral Not applicable to this project. „Achieving Sustainable Development‟ Objective 8
NPPF Protecting Green Belt land. Neutral The entire Project will be constructed within existing Secretary „Achieving Sustainable Development‟ of State land and so will not result in further loss of Green Belt. Objective 9 NPPF Meeting the challenge of climate change, flooding Neutral The Project only involves the construction of a relatively small „Achieving Sustainable Development‟ and coastal change. area of additional hard standing. The ERAs provide Objective 10 attenuation over and above what is require for their increase in impermeable areas. The discharge rates pre- and post-Project will be consistent.
The proposed drainage design does not include mitigation for the potential increase in flood risk caused by constructing ERAs in the floodplain. Further assessment is required to identify the significance of this effect and potential requirement for additional storage. Without such mitigation (if necessary), the scheme would not meet the requirements of PPS25 and a number of local policies highlighted in section 5. However, if additional storage is provided the scheme should be compliant with PPS25 and the local policies regarding flood risk.
NPPF Conserving and enhancing the natural Mix of adverse and There would be minor changes in noise levels experienced „Achieving Sustainable Development‟ environment – beneficial with the Project. Low noise surfacing would be installed as Objective 11 - protecting and enhancing valued landscapes, part of general maintenance by 2030 and the Project would geological conservation interests and soils; divert traffic off local roads onto the motorway. Decrease in noise levels also attributed to reduced traffic speeds. - recognising the wider benefits of ecosystem services; Air quality would experience negligible change as a result of
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Policy Objectives Significance of Comment Effect - minimising impacts on biodiversity and providing the Project. net gains in biodiversity where possible, The Project would result in a very small increase in contributing to the Government‟s commitment to contamination of surface water draining to receiving halt the overall decline in biodiversity, including by watercourses, although as water quality is already poor the establishing coherent ecological networks that are change due to the Project is assessed as neutral. more resilient to current and future pressures; In terms of biodiversity, the project would have a slight adverse - preventing both new and existing development effect through loss of verge habitats. These habitats are no from contributing to or being put at unacceptable greater than „lower‟ in value. However the scheme does not risk from, or being adversely affected by restrict access to nature. unacceptable levels of soil, air, water or noise pollution or land instability; - remediating and mitigating despoiled, degraded, derelict, contaminated and unstable land, where appropriate. NPPF Conserving and enhancing the historic Neutral The proposed Project would have some minor impacts on „Achieving Sustainable Development‟ environment. designated heritage assets. Given that the M25 is already in Objective 12 existence, along with a number of gantries, the proposed Project will lead to a very minor intensification of the presence and appearance of the carriageway however, no designated heritage assets will be substantially harmed as a result the construction and operation of the Project.
There will be no significant effects on any designated heritage assets as a result of the Project giving an overall assessment of slight adverse for cultural heritage.
NPPF Facilitating the sustainable use of minerals. Neutral Not applicable to this project. „Achieving Sustainable Development‟ Objective 12
The London Plan July 2011
Policy 2.3 Growth Areas Work with other agencies to develop links between Beneficial This scheme improves the ability for traffic to move and Coordination Corridors London and growth areas and ensure appropriate between the A1 and M11 which improves the links resources are available. between areas.
Policy 2.6 Outer London Build links with the diversity of outer London. Neutral This proposal will not have affect on the diversity of outer London.
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Policy Objectives Significance of Comment Effect
Policy 2.8 Transport Outer Enhancing links between different transport modes. Neutral This proposal will not affect existing transport modes London. other than motorway traffic which is a combination of traffic users. Policy 5.1 Climate Change Reduce Carbon Dioxide emissions. Adverse Carbon emissions would increase with the Project. Mitigation
Policy 5.2 Minimising CO² How to reduce CO² in development. Adverse Carbon emissions would increase with the Project
Policy 6.1 Transport Closer integration of transport through sustainable Neutral This proposal will not affect existing transport modes Strategic Approach measures. other than motorway traffic which is a combination of traffic users. Policy 6.4 Enhancing Effective transport policies across the regions. Beneficial This proposal would significantly contribute to meeting London‟s Transport this policy objective in improving transport connectivity Connectivity with less congestion.
Policy 6.11 Smoothing Develop intelligent transport systems for users. Beneficial The proposal uses an innovative way to reduce Traffic Flow and tackling congestion and keep drivers aware of the road Congestion conditions. Policy 6.12 Road Network New extensions and or providing new links to address Beneficial This proposal realises the need to increase capacity Capacity the needs of users. within minimal disruption. Policy 7.14 Improving Air That all development should support improvements to air Neutral Air quality would experience negligible change as a result Quality quality. of the Project. Policy 7.15 Reducing Reduce noise. Neutral There would be a minor decrease in noise levels Noise and Enhancing experienced in 2030 with the Project, when compared Soundscapes with 2015 without the Project. No mitigation measures are proposed as part of the Project, but low noise surfacing would be installed as part of general maintenance by 2030 and the Project would divert traffic off local roads onto the motorway. Decrease in noise levels also attributed to reduced traffic speeds.
Policy 7.16 Green Belt Protect the green belt from inappropriate development. Neutral Green Belt covers the entire Study Area with the exception of the built areas of Potters Bar, Waltham Cross and North Enfield. The entire Project will be constructed within existing Secretary of State land and
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Policy Objectives Significance of Comment Effect so will not result in further loss of Green Belt.
Policy 7.19 Biodiversity Ensure positive gains for nature through development. Adverse In terms of biodiversity, the Nature Conservation and Access to Nature chapter estimates the project would have a slight adverse effect on biodiversity. There would be slight loss of verge habitats, although these are no greater than „lower‟ value. By using the hard shoulder to provide additional capacity, the Project design is minimising land take thereby reducing impacts of development upon biodiversity
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13.5 Indication of Any Difficulties Encountered 13.5.1 The assessment for this Chapter was a simple assessment. The assessment of impacts is not exhaustive and takes into account the impacts associated with both the construction phase and the operational phase for National and Regional policies only. There are regular changes and reviews of policy documents and this should be considered as part of the project that plans and policies are subject to change. 13.6 Summary 13.6.1 At the national level, the Project is generally in compliance with various DfT, HA and the Department for Communities and Regional plan policies that promote improvements to the existing trunk road network/freight corridor including: Improving journey time reliability Increasing road capacity Improving safety Net benefit for noise Accessibility 13.6.2 However, there are some adverse effects of the Project hindering the objectives of improving air quality and reducing CO2 emissions. 13.6.3 There would be adverse effects on policies related to biodiversity, as there would be minor loss of verge habitats, although none are of greater than „lower‟ value. No biodiversity enhancement measures are being proposed. There would be adverse effects in relation to landscape policies and plans due to visual impacts from additional gantries and signage and vegetation loss. 13.6.4 At the national level the project is in general compliance with various DfT, HA and CLG and policies that promote improvements to existing trunk road, network and freight corridor with an overall beneficial effect. The sustainable use and management of the existing highway network, increasing capacity through utilising the hard shoulder would meet the overarching objective of the National Planning Policy Framework of sustainable development
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14. Road Drainage and the Water Environment 14.1 Study Area 14.1.1 For the purposes of this report the study area has been set at 500m either side of the scheme centre line. Within this area constraints due to the sensitivity of the water environment have been considered as well as potential impacts from the proposed scheme. 14.1.2 There are three surface water catchments in the study area; the River Colne, the River Lee and the River Roding. The dominant catchment is the River Lee and a number of its tributaries cross the proposed scheme area. 14.2 Baseline Conditions 14.2.1 Information on the water environment has been collected for previous studies and has been updated where necessary. Surface Water Quality 14.2.2 Within the study area, the M25 crosses or is intersected by more than 20 watercourses (see Table 14.1 below and Figure 14.1). Many of the receiving watercourses in the study area are relatively small and dilution is limited. Moreover, some watercourses receive road drainage through a number of outfalls at intervals along their course. 14.2.3 Nine of the watercourses identified in Table 14.1 are classified under the Water Framework Directive (WFD). The target and current status of these waterbodies are summarised in Table 14.2 below and on Figure 14.1. The main river catchment is listed in brackets. Information on current status and WFD objectives is taken from the „Classification Status and Objectives for Water Framework Directive Cycle‟, published in River Basin Management Plans in Annexes A and B and updated in January 20111. Table 14.1 - Watercourses in the Study Area Grid reference Name WFD designated watercourse 5267 2000 Salmons Brook
5303 2006 Turkey Brook
5317 2006 Cuffley Brook
5345 2000 New River Aqueduct
5372 1999 Small River Lee
5375 1999 River Lee
5375 1998 River Lee Navigation Channel
5385 1999 and Cobbin‟s Brook 5436 2009
5231 1999 Mimshall Brook
5231 1999 Mimshall Brook/Watery Path
5376 1999 Horsemill Stream
5376 1999 Old River Lee / River Lee
1 Available at http://www.environment-agency.gov.uk/research/planning/125035.aspx
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Grid reference Name WFD designated watercourse Diversion
5408 1998 Ford
5433 2009 Drain to Reservoir
5476 1998 River Roding
5468 1996 River Roding Drains
5404 1997 Beech Hill Culvert (Tributary to Cobbin‟s Brook)
5408 1998 Honey Lane Culvert (Tributary to Cobbin‟s Brook)
5426 2006 Crown Hill Culvert
5436 2009 The Warren Culvert (Tributary to Cobbin‟s Brook)
5459 2009 Ivy Chimneys Culvert (Tributary to River Roding)
5472 1997 Brookhouse Brook, (Tributary to River Roding)
Table 14.2 - Target and Current Status of WFD Designated Stretches of Watercourses in the Study Area Grid Name WFD classification Overall objective WFD Current reference / designation status (date for overall WFD achieving objective) status 5267 2000 Salmons Brook Heavily modified Good potential (2015 Poor (River Lee) waterbody chemical, 2027 ecological)
5231 1998 Mimshall Brook Protected area (for Good (2015 chemical; Moderate (River Colne) economically 2027 ecological) significant species)
5303 2006 Turkey Brook Protected area (for Good (2027) Moderate (River Lee) economically significant species)
5317 2006 Cuffley Brook Protected area (for Good (2027) Moderate (River Lee) economically significant species)
5372 1999 Small River Lee Protected area (for Good (2015) Good (River Lee) economically significant species)
5375 1998 River Lee Heavily modified Good potential (2027) Moderate Navigation waterbody Channel (River Protected area (for Lee) economically significant species)
5385 1999 Cobbin‟s Brook Protected area (for Good (2027) Bad (River Lee) economically significant species)
5457 2004 Brookhouse Good (2027) Poor
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Grid Name WFD classification Overall objective WFD Current reference / designation status (date for overall WFD achieving objective) status Brook (River Roding)
Salmons Brook 14.2.4 Salmons Brook is classified as a Protected Area (for Economically Significant Species (Freshwater Fish Waters)) under the WFD. The Brook has an overall target of Good Potential, with achievement of High Chemical status by 2015 and Good Ecological Potential by 2027. The current and predicted status in 2015 is Poor. Mimshall Brook 14.2.5 Mimshall Brook forms part of the eastern arm of the River Colne. Approximately 4 km downstream (north) of the M25, the Mimshall Brook sinks through various swallow holes into the groundwater at Waters End. It is thought to rise again 2km west at the River Colne, although tracer experiments have shown that on occasion it may also feed the River Lee catchment (Stage 2 EAR 2009). 14.2.6 Mimshall Brook is classified as a Cyprinid Fishery under the Surface Waters (Fishlife) Classification Regulations (which transposes the EC Freshwater Fish Directive (75/659/EEC). The Brook is also now classified as a Protected Area (for Economically Significant Species (Freshwater Fish Waters)) under the WFD. The Brook has an overall target of Good status by 2027 with targets of High Chemical Status by 2015 and Good Ecological Status by 2027. The current and predicted status in 2015 is Moderate, the limiting factor being invertebrates. The current status for both copper and zinc is High. Turkey Brook 14.2.7 Turkey Brook is classified as a Cyprinid Fishery under the Surface Waters (Fishlife) Classification Regulations from its source to the Small River Lee. This is now also classified as a Protected Area (for Economically Significant Species (Freshwater Fish Waters)) under the WFD. The Brook has an overall target of Good Status by 2027 with Good Ecological status also by 2027. The current and predicted (2015) status is Moderate. Cuffley Brook 14.2.8 Cuffley Brook shares the same classifications as Turkey Brook. River Lee, Small River Lee and River Lee Navigation 14.2.9 There are several interconnections between the Small River Lee, the River Lee Navigation Channel and the River Lee, though they are given separate designations. 14.2.10 The Small River Lee is designated a Cyprinid Fishery and now Protected Area (for Economically Significant Species (Freshwater Fish Waters)), under the WFD. It has an overall WFD target of Good Status by 2015 with Good Ecological Status also by 2015. Current status of the Small River Lee is already Good and it is predicted to retain this status in 2015. 14.2.11 The River Lee Navigation Channel is a canalised section of the River Lee and is designated as a Heavily Modified Waterbody. It is designated a Cyprinid Fishery and now Protected Area (for Economically Significant Species (Freshwater Fish Waters)) under the WFD. It has an overall target of Good Potential by 2027 with Good Ecological Potential also by 2027. The current and predicted status in 2015 is Moderate Potential.
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Cobbin‟s Brook 14.2.12 Cobbin‟s Brook is a tributary of the River Lee. It is designated a Cyprinid fishery from source to the River Lee and a now Protected Area (for Economically Significant Species (Freshwater Fish Waters)) under the WFD. The Brook has an overall target of Good Status by 2027 with Good Ecological Status also by 2027. The current status is Bad, the limiting factor being invertebrates. The Brook‟s predicted status by 2015 is Moderate. Brookhouse Brook 14.2.13 Small tributaries of the River Roding are crossed after the Bell Common Tunnel at the eastern end of Section 5. The Brookhouse Brook is the main tributary of the River Roding and has an overall target of Good Status by 2027 with Good Ecological Status also by 2027. Current status is Poor, the limiting factors being macrophytes and phosphate. Groundwater 14.2.14 The existing drainage in Section 5 is all to surface water and there are no soakaways. 14.2.15 Throughout the majority of Section 5 the underlying chalk aquifer is confined below London Clay which is largely impermeable and defined as a non-aquifer. However, there are some protected groundwaters in the study area, see Figure 14.1. An outer and inner groundwater Source Protection Zone (SPZ) associated with a groundwater abstraction borehole is located west of Junction 25. An outer and inner groundwater SPZ is also found to the east of Junction 25, mid- way between Junction 25 and 26 in the Lee Valley. A minor bedrock and superficial aquifer of intermediate leaching potential and low leaching potential is located west of Junction 27 at Epping but it is not designated as an SPZ. 14.2.16 There are two Water Framework Directive (WFD) groundwater bodies which fall into the project area: Radlett Tertiaries and the North Mimms Tertiaries. North Mimms Tertiaries 14.2.17 The current WFD status of the North Mimms Tertiaries is poor. The quantiative status of the North Mimms Tertiaries is poor and it is failing on chemical status. It has an overall objective of Good Status by 2027 with Good Ecological Status by 2027 and Good Chemical Status by 2021. Radlett Tertiaries 14.2.18 The current WFD status of the Radlett Tertiaries is poor. The quantitative status of the Radlett Tertiaries is poor and it is failing on chemical status. It has an overall objective of Good Status by 2027 with Good Chemical Status by 2015. Flood Risk 14.2.19 The Environment Agency Flood Map shows that the majority of the study area is not at risk of flooding (see Figure 14.1). However, an area between Junction 25 and 26, to the north and south of the carriageway in the Lee Valley, may be affected by fluvial flooding with a 1 in 1000 chance of occurring in each year (0.1%), see Figure 14.1. 14.2.20 In addition to the Lee Valley, there are areas at risk of fluvial flooding where the motorway crosses the following watercourses (see Figure 14.1): Mimshall Brook – to the east of Junction 23 Turkey Brook – between Junction 34 and 25 Cuffley Brook – between Junction 24 and 25 Cobbin‟s Brook – to the west of Junction 26 Tributary of Cobbin‟s Brook – north of the carriageway, between Junction 26 and 27 Brookhouse Brook – to the west of Junction 27.
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14.2.21 Hertsmere Borough Council Strategic Flood Risk Assessment (SFRA) indicates that there have been few historic groundwater or surface water flooding incidents in the Study Area. There is one record of groundwater flooding to the north of the M25 at South Mimms Services and an incident of drainage infrastructure flooding on Barnet Road where it crosses the M25. 14.2.22 The Broxbourne Borough Council SFRA indicates that there have been historic incidents of surface water flooding in the study area. Surface water flooding has occurred in the past at junction 26 of the M25 due to overtopping of gullies. There have been a number of incidents of surface water flooding in Waltham Cross and Waltham Abbey due to insufficient drainage capacity and a collapsed water main. 14.2.23 The Welwyn and Hatfield Borough Council SFRA indicates that the risk of flooding from pluvial and artificial sources in the Borough is low. The limited number of records of groundwater flooding in the Borough prevents classification of flood probability. 14.2.24 The London Borough of Enfield SFRA indicates that there is a risk of groundwater flooding to the south of the M25 at the interface between geological strata capable of carrying significant quantities of water and impermeable London Clay. However, the overall risk of groundwater flooding is considered low. Surface water flooding issues in the Borough are generally related to the performance of existing drainage infrastructure. However, there have been no recorded incidents of surface water flooding on the M25 in the Borough. There is also a risk of flooding from artificial sources in the Borough, including The New River (part of the River Lee Navigation) which crosses the M25 at the eastern edge of the Borough. Road Drainage 14.2.25 Existing drainage plays a role in the treatment of highway runoff despite not being specially designed to have a treatment function. Highway runoff is treated inherently through the use of filter drains and pipe and gullies draining to ditches and passing through oil interceptors to the watercourses. There are 24 outfalls that currently drain to surface watercourses from the carriageway. Treatment of road drainage is provided by the existing drainage network which is a combination of filter drains and kerb and gully drainage. Environmental Designations 14.2.26 There is one Site of Special Scientific Interest (SSSI) within 500m of the scheme boundary. Epping Forest SSSI lies approximately 250m (at its closest point) south of the M25 between junctions 26 and 27. It is designated for its ancient semi-natural woodland and wood-pasture habitat as well as scattered wetland habitats. There is an abundance of bogs, pools and ponds in the Forest, some of which support rare invertebrates and amphibian assemblages. Changes to water levels and drainage structures and erection of permanent or temporary structures are operations considered likely to damage the special interest of the site. 14.3 Methodology 14.3.1 The potential effects of the extra areas which are part of the MM scheme design (i.e. Emergency Refuge Areas (ERAs) and slip-road widening) on the water environment have been assessed. 14.3.2 The reporting of potential effects follows the approach set out in the DMRB (HD45/09) Tables A4.1 – A4.6 (DMRB HD45/09). This involves identifying attributes of the water environment, their importance, the magnitude of impacts on attributes and finally the significance of potential effects. It should be noted that not all aspects of the guidance were followed, as laid out below. Attributes 14.3.3 Attributes of the water environment in the study area have been identified using Table A4.1 from the DMRB (HD45/09). Water environment attributes in the study area are: Surface water
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Groundwater Floodplain. Importance of Attributes 14.3.4 The DMRB (HD45/09) criteria in Table A4.3 have been used to identify the importance of the water environment attributes in the study area. The criteria are shown in Table 14.3. Table 14.3 - Summary of the Water Environment Importance Assessment Criteria Importance Criteria Very High Attribute has a high quality and rarity on a national scale High Attribute has a high quality and rarity on a local scale Medium Attribute has a medium quality and rarity on a local scale Low Attribute has a low quality and rarity on a national scale
Magnitude of Impacts Surface water - operational impacts 14.3.5 Operational impacts of a scheme on surface water are usually assessed by looking at impacts due to additional runoff and increased spillage risk. Changes in drainage may also impact on water quality. Changes in water quality as a result of operation of the scheme may affect the status of waterbodies classified under the WFD. 14.3.6 However, the risks to surface water as a result of the operation of Emergency Refuge Areas (ERAs) and widened slip roads have been considered in the design of the scheme by professional judgement. Increased potential for spillage on the ERAs was addressed and appropriate mitigation included in the design. As such, a WFD Assessment is not required to understand the operational effects of the scheme on designated watercourses. 14.3.7 For this study the assessment of the overall drainage system for the road has been scoped out as operational impacts of the whole road will be assessed as part of the Priority Outfalls scheme, a separate initiative being centrally co-ordinated by the Highways Agency. The Priority Outfalls scheme will assess the impacts of the operation of the motorway and trunk road network taking into account all the outfalls. The operational impact of this section of the M25 will be included in the Priority Outfall scheme. 14.3.8 The aim of the Priority Outfalls scheme is to identify priority outfalls on the drainage network that are at risk of polluting the surface water courses that they flow into, so that mitigation measures can be designed and installed. Outfalls are classified A-E depending on the level of perceived risk to surface watercourses. Methods A and B from the DMRB (HD45/09) are used to assess the risk of pollution from routine runoff at a surface water course and Method D determines the risk that a spillage accident will occur within the area of road draining to the outfall, and whether that accident will lead to a pollution incident . The outcome of Methods A, B and D will determine the category the outfall is in. Mitigation will be recommended as necessary following the assessment. Surface water - construction impacts 14.3.9 Surface water impacts could occur during the construction phase as a result of contaminated site runoff or spillages from various sources such as construction vehicles, machinery and fuel stores. Construction events are likely to be in the form of spills or one off events leading to an immediate impact rather than a continuous discharge. 14.3.10 A methodology for assessing the magnitude of potential impacts during construction at each of the ERAs has been developed based on professional judgement. The method is also based on a WFD assessment i.e. data gathering, identification of impacts on waterbodies and mitigation to avoid impacts. However, a full WFD assessment is not required to assess construction impacts on
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surface water as construction events are likely to be in the form of spills or one off events leading to an immediate impact rather than a continuous discharge.The magnitude of construction impacts on surface water is defined in terms of proximity of watercourses to construction of ERAs and slip road widening, see Table 14.4. The distance from the proposed ERA and slip road widening locations to watercourses has been measured using the Multi Agency Geographic Information for the Countryside (Magic) website.
Table 14.4 - Magnitude of Construction Impacts – Surface Water
Proximity to watercourse Magnitude of impact < 100m High 100 – 500m Medium >500m Low
Groundwater - operational impacts 14.3.11 Additional runoff and potential spillages from the operation of ERAs and widened slip roads may have an effect on groundwater. Changes in drainage may also affect groundwater. Changes in water quality as a result of operation of the scheme may affect the status of groundwater bodies classified under the WFD. 14.3.12 For this scheme there are no direct discharges to ground, so no detailed assessment of the operational impacts or WFD assessment has been considered using the guidance from DMRB (HD45/09). Additionally, as ERAs are not associated with an increase in traffic, it was not possible to use DMRB Method C. However the local operational impacts on groundwater as a result of ERAs and widened slip roads have been considered by professional judgement in the design of the scheme and appropriate mitigation included. Groundwater - construction impacts 14.3.13 During the construction phase there is potential for contaminated site runoff and accidental spillages to interact with groundwater. Excavations could also open up pathways to groundwater. This is assessed in Chapters 9 and 10. 14.3.14 A methodology for assessing the magnitude of construction impacts has been developed based on professional judgement. The method is also based on a WFD assessment i.e. data gathering, identification of impacts on groundwater bodies and mitigation to avoid impacts. However, a full WFD assessment is not required to assess construction impacts on groundwater as construction events are likely to be in the form of spills or one off events leading to an immediate impact rather than a continuous discharge. 14.3.15 The magnitude of construction impacts is defined in terms of proximity of protected groundwater to construction of ERAs and slip road widening, see Table 14.5. The distance from the proposed locations of ERAs and slip road widening to source protection zones has been measured using the Multi Agency Geographic Information for the Countryside (Magic) website.
Table 14.5 - Magnitude of Construction Impacts – Groundwater Proximity to source protection zone Magnitude of impact < 100m High 100 – 500m Medium >500m Low
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Floodplain – operational impacts 14.3.16 Flood risk could be increased if there is an increase in runoff as a result of an increase in impermeable surface. However, increased volumes have been calculated and attenuation built into the design (see section 14.6) so this impact will not be assessed further. 14.3.17 Constriction of existing watercourses by culverting under ERAs or widened slip roads could also increase flood risk. However, the design does not include lengthening any culverts, so this impact is not assessed further. Floodplain - construction 14.3.18 Flood risk could increase if there is a loss of flood storage caused by construction of ERAs or slip road widening in the floodplain. Assessment Methods E and F set out in the DMRB (HD45/09) have not been used to identify the magnitude of impacts. As operational impacts of ERAs and slip road widening have been scoped out, and ERAs are not associated with an increase in traffic, it was not possible to use DMRB Methods E and F. As such, a methodology for assessing the magnitude of impacts has been developed based on professional judgement. 14.3.19 The magnitude of construction impact is defined in terms of which Flood Zone (on the Environment Agency Flood Map) proposed ERA and slip road widening locations are in, see Table 14.6. 14.3.20 Flood Zone 1 is classified by the Environment Agency as having a low probability of flooding, with an annual probability of flooding is lower than 0.1% for either fluvial or sea flooding. Land in Flood Zone 1 is likely to have a low sensitivity to construction of ERAs and slip road widening. 14.3.21 Flood Zone 2 has a medium probability of flooding with an annual probability of flooding between 0.1 and 1.0% for fluvial flooding. Land in Flood Zone 2 is likely to have a medium sensitivity to construction of ERAs and slip road widening. 14.3.22 Flood Zone 3 has a high probability of flooding with an annual probability of flooding of 1.0% or greater for fluvial flooding. Land in Flood Zone 3 is likely to be highly sensitive to construction of ERAs and slip road widening. 14.3.23 Flood risk will need to be assessed for all construction works within Flood Zones 2 and 3. However, at this stage the level of piling relative to flood levels at each of the ERAs is not known. Once this is known, further flood risk assessment may be required for ERAs in Flood Zones 2 and 3. 14.3.24 Works within 8 meters of the top of the bank of a main river require consent from the Environment Agency.
Table 14.6 - Magnitude of Construction Impacts – Floodplain Flood Zone Magnitude of impact Flood Zone 3 High Flood Zone 2 Medium Flood Zone 1 Low
Significance of Effects 14.3.25 The significance of effects has been determined by considering the importance of the water attributes and the magnitude of impacts (as defined in section 14.3 above). The potential overall significance of the effect on the water environment has been assessed using the criteria outlined in Table 14.7. The level of significance is assigned after consideration of any proposed mitigation. 14.3.26 For the purpose of this assessment, the classification of significance (most significant to insignificant) is a relative measure. The significance classification indicates the relative potential
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for an effect on water assets from construction of each ERA and length of slip road widening. A significance classification of „most significant‟ indicates that construction of that ERA or slip road widening is most likely to have an effect on the water asset. A classification of „more significant‟ indicates that construction of that ERA or slip road widening is more likely to have an effect on water assets than those classified as „less significant‟.
Table 14.7 - Summary of Significance of Effect Criteria
Very High More significant More significant Most significant
High Less significant More significant Most significant
Medium Less significant Less significant More significant attribute attribute
Importance of of Importance Low Insignificant Less significant Less significant
Low Medium High
Magnitude of impact
14.4 Value (Sensitivity) of Resource 14.4.1 The importance of water environment attributes in the study area has been assessed according to the criteria in Table 14.3 and by considering the baseline information presented above. Surface Water 14.4.2 Surface watercourses provide a range of environmental services, including water supply, conveyance of flood water, dilution and removal of effluent, recreation and biodiversity. 14.4.3 All WFD watercourses have an overall objective of Good status and could therefore be considered to be at least High importance. However, as this assessment focuses on construction impacts in the relatively short term, the importance of surface water assets has been assessed based on current WFD status. Importance also depends on current classification under the Freshwater Fish Directive and either international or national habitat designations. 14.4.4 The importance of watercourses in the study area is summarised in Table 14.8.
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Table 14.8 - Importance of Watercourses in the Study Area Watercourse Current WFD Freshwater fisheries Importance status designation Salmons Brook Poor Undesignated Low Mimshall Brook Moderate Cyprinid fishery Very High Tributary of Mimshall Brook Undesignated Undesignated Low Turkey Brook Moderate Cyprinid fishery Very high Tributary of Turkey Brook Undesignated Undesignated Low Cuffley Brook Moderate Cyprinid fishery Very high Tributary of Cuffley Brook Undesignated Undesignated Low Tributary of Turkey Brook Undesignated Undesignated Low New River Aqueduct Undesignated Undesignated Low Small River Lee Good Cyprinid fishery Very high River Lee Undesignated Undesignated Low Tributary of River Lee Undesignated Undesignated Low River Lee Navigation Channel Moderate Cyprinid fishery Very high Cobbin‟s Brook Bad Cyprinid fishery Very high Horsemill Stream Undesignated Undesignated Low Old River Lee / River Lee Undesignated Undesignated Low Diversion Ford Undesignated Undesignated Low Drain to Reservoir Undesignated Undesignated Low River Roding Undesignated Undesignated Low River Roding Drains Undesignated Undesignated Low Beech Hill Culvert (Tributary to Undesignated Undesignated Low Cobbin‟s Brook) Honey Lane Culvert (Tributary to Undesignated Undesignated Low Cobbin‟s Brook) Crown Hill Culvert Undesignated Undesignated Low The Warren Culvert (Tributary to Undesignated Undesignated Low Cobbin‟s Brook) Ivy Chimneys Culvert (Tributary Undesignated Undesignated Low to River Roding) Brookhouse Brook, (Tributary to Poor Undesignated Low River Roding) Tributary of Brookhouse Brook Undesignated Undesignated Low
Groundwater 14.4.5 Most of the study area is underlain by non-aquifer and is generally of Low importance for groundwater. However, in the limited areas which are underlain by major aquifers the importance is rated as High for outer SPZs and Very High for inner SPZs. The importance of protected groundwater is shown in Table 14.9. Outside of these areas, importance is considered to be Low.
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Table 14.9 - Importance of Groundwater Attributes in the Study Area Location Groundwater designation Importance East of Junction 23 Inner SPZ Very high West of Junction 25 Inner and Outer SPZ Very high Mid-way between Junction 25 and 26 Inner and Outer SPZ Very high
Floodplain 14.4.6 Floodplains which protect more than 100 properties are considered Very High importance, those which protect between 1 and 100 properties are High importance, fewer than 10 properties and the floodplain is considered Moderate importance. If the floodplain has limited constraints or a low probability of flooding it is considered Low importance. 14.4.7 Most of the watercourses have only minor downstream development within Flood Zone 3. However, there are significant flood risk areas downstream of the proposed scheme on the River Lee. The floodplain attribute in the study area is, therefore, generally of Low importance but High for the River Lee valley where there are a significant number of properties. 14.5 Regulatory and policy framework National 14.5.1 The main pieces of national legislation pertinent to the water environment in the study area include the following: The Highways Act 1980, as amended Water Resources Act 1991, as amended Land Drainage Act 1991, as amended Environment Act 1995, as amended The Water Environment (Water Framework Directive) (England and Wales) Regulations 2003 (which transposes the Water Framework Directive 2000/60/EC) The Surface Waters (Fishlife) (Classification) Regulations 1997 (amended 2003) (which transposes the EC Freshwater Fish Directive 78/659/EEC) The Groundwater Regulations 1998 as amended (which transposes the EC Groundwater Directive 80/68/EC) The Surface Waters (Dangerous Substances) (Classification) Regulations 1998 (which transposes the EC Dangerous Substances Directive 76/464/EEC and daughter directives) The Water Supply (Water Quality) Regulations 200 (which transpose the EC Drinking Water Directive 98/83/EEC). 14.5.2 The Department for Communities and Local Government (DCLG) determines national planning policy which is set out in the National Planning Policy Framework (NPPF). Local Authorities must take account of national planning policies when preparing plans. 14.5.3 The NPPF states that “inappropriate development in areas at risk of flooding should be avoided by directing development away from areas at highest risk, but where development is necessary, making it safe without increasing flood risk elsewhere”. It also states that “the planning system should contribute to and enhance the natural and local environment by preventing both new and existing development from contributing to or being put at unacceptable risk from, or being adversely affected by unacceptable levels of soil, air, water or noise pollution”
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14.5.4 The Environment Agency has also published documents which are relevant to this assessment: Policy and Practice for the Protection of Groundwater - details the conceptual basis for the risk based decision making and policy statements in areas such as diffuse pollution of groundwater and the control of groundwater abstraction. Pollution Prevention Guidance (PPG) notes - give advice on the law and good environmental practice, to help reduce environmental risks. PPG notes of particular relevant to this scheme include: - PPGN01 - General guide to the prevention of pollution - PPGN02 - Above ground oil storage tanks - PPGN03 - The use and design of oil separators - PPGN05 - Works in or near water - PPGN06 - Working at construction and demolition sites - PPGN08 – Safe storage and disposal of used oils - PPGN13 – Vehicle washing and cleaning - PPGN18 - Control of spillages and fire fighting run-off - PPGN22 - Dealing with spills Regional The London Plan 2011 14.5.5 The London Plan 2011 includes policies S12 (Flood Risk management) S13 (Sustainable Drainage) and S14 (Water Quality and Waste Water Infrastructure) Policy S12 says that the mayor will work with all agencies to address current and future flood issues and minimise risk in a sustainable and cost effective way. Policy S13 encourages the use of Sustainable drainage Systems where practical. Policy S14 says that the Mayor will work in partnership to ensure London has the appropriate waste water infrastructure. East of England Plan 2008 14.5.6 East of England Plan 2008 includes Policy WAT4 (Flood Risk management) which says that flood risk is a significant issue in the East of England and that it is a priority to defend existing properties from flooding and for development to be located where there is little or no flood risk. Local Hertsmere Local Plan 14.5.7 Hertsmere Borough Council Local Plan (Hertsmere Borough Council, 2003) includes the following policies: Policy D1: Watercourses, River Corridors, Flood plains and Water Meadows “Development, including culverting of watercourses, will not be permitted where it would have an adverse impact on the Borough‟s watercourses, river corridors, floodplains and water meadows. “ Policy D3: Control of Development Drainage and Run off Considerations “Planning permission will not be granted for development within areas at risk of flooding unless it incorporates appropriate flood protection measures.” Hertsmere Consultation Core Strategy 14.5.8 Hertsmere Consultation Core Strategy 2010 includes the following policy
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Policy CS15 which says that the Council will work with partners to ensure development does not increase levels of flood risk. Broxbourne Local Plan 14.5.9 Borough of Broxbourne Local Plan (Borough of Broxbourne, 2005) includes the following policies: SUS15: Ground and Surface water protection: “Planning permission will not be granted for development which poses a threat to the quality of either surface of groundwater.” SUS16: Flood Risk Assessments “(i) development in areas of flood risk will only be permitted where a flood risk assessment has been carried out or environment agency advice indicates an assessment is not required.” SUS17: Flood Prevention: “The susceptibility of land to flooding is a material planning consideration. Uncertainties are inherent in the prediction of flooding and flood risk and are expected to increase as a result of climate change. The council will apply the precautionary principle to the issue of flood risk in determining planning applications. “ Broxbourne Submission Core Strategy 14.5.10 Broxbourne Submission Core Strategy 2010 includes the following policy CS8 – Environment; which says that the Council will work with the Environment Agency to enhance the water environment, reduce flood risk in accordance with guidance and evidence. Welwyn Hatfield District Plan 14.5.11 Welwyn Hatfield District Plan (Welwyn Hatfield Borough Council, 2005) includes: R8: Floodplains and Flood Prevention: “Within the floodplains identified on the Proposal Map, planning permission for development will not be granted where proposals would ;(i) Decrease the capacity of the floodplain to store flood water; or (ii) Impede the flow of water; or (iii) Increase the number of people and properties at risk from flooding.” R9: Water Supply and Disposal: “Permission will not be granted for proposals that: (i) Would be detrimental to existing water abstractions, fisheries, amenity and nature conservation; (ii) Would cause adverse change in flows or levels in the groundwater, or any rivers, streams, ditches, springs, lakes or ponds in the vicinity..” Policy R10: Water Conservation Measures: “New development will be expected to incorporate … sustainable drainage systems…” Enfield Unitary Development Plan 14.5.12 The London Borough of Enfield Unitary Development Plan (London Borough of Enfield, 1994) includes: Policy (I) EN6: “To have regard to the need to minimise the environmental impact of all developments and in particular to … assess flooding and surface water drainage implications of proposed developments.” Enfield Core Strategy 14.5.13 Enfield Core Strategy includes the following policies: Policy CP 28
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„The Council will take a risk approach to development and will direct development away from areas at risk of flooding. Policy CP29 Refers to managing flood defence infrastructure. Epping Forest Local Plan 14.5.14 Epping Forest Local Plan (Epping Forest District Council, 2008) includes: Policy RP3: Water Quality: “The Council … will refuse permission for developments or activities which present an undue risk to the quality and quantity.” Policy U2A: Development in flood risk areas: “Development proposals within the Environment Agency‟s currently designed Flood Risk Zones will be determined in accordance with a sequential approach as set out the Technical Appendix to the National Planning Policy Guidance which now supersedes PPS25.” Policy U3A: Catchment effects: “The Council will not permit development which would result in either: (i) increased risk of flooding or a reduction in the effectiveness of existing flood defence measures, either on site or elsewhere within the catchment; or (ii) significant adverse effects upon a watercourse, navigable waterway or sewerage infrastructure, unless it is satisfied that adequate and appropriate attenuation measures, such that there is no increase in the risk of flooding, are incorporated as part of the development.” Policy U3B: Sustainable drainage systems: “…the Council may require developments to include sustainable drainage systems to control the quality or attenuate the rate of surface water run-off.” 14.6 Design, Mitigation and Enhancement Measures Proposed Drainage Design 14.6.1 In accordance with IAN161/12, the scheme design will minimise changes to the drainage system. 14.6.2 Drainage design will be carried out in accordance with the DMRB. In addition to the DMRB other design standards which may be used as required are set out in the Drainage Design Input Statement and Drainage Design Rationale. 14.6.3 Drainage design pertinent to the ERAs and slip road widening is described in the Drainage Design Input Statement (see Appendix G) and is summarised below. 14.6.4 Storage/attenuation together with flow controls will be provided online at suitable locations on the verge side. This is to provide the required outfall discharge rate and overcome insufficient system storage due to excessive surcharging as a result of increased contributing areas from additional paved areas and application of climate change allowance on the additional paved areas. Any storage/attenuation is to be designed for the 1 in 5 year event. ERAs 14.6.5 ERAs will be drained separately to the main carriageway. Drainage will entail gullies connected to a dedicated pipe work passing through chambers with 2 cubic meters storage capacity for accidental spillage and a penstock/sluice valve shut off facility before connecting into the existing drainage system. 14.6.6 Where the main carriageway falls towards the ERA, a slot drain will be provided across the front of the ERA to collect surface water run-off from the carriageway and connected back into the existing pipe work system.
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14.6.7 Where the ERA is on the high side of the carriageway on embankment and no existing drainage in the verge exists, the ERA will be drained into the existing collector drain or ditch at the toe of the embankment. Where no drainage at the toe of embankment exists, the ERA will be drained to the central reserve requiring a new cross pipe across the carriageway. Slip road widening 14.6.8 Where carriageway widening is to take place on the verge side, existing drains will be replaced. Potential Impacts 14.6.9 Potential impacts to the water environment may occur as a result of construction and operation of the scheme. Surface water – operational 14.6.10 The operation of the scheme could impact on surface water due to additional runoff and increased spillage risk. There is potential for contaminated material or sediment deposited on the ERAs to be washed off by rainfall during operation of the scheme. Changes in drainage may also impact on water quality. 14.6.11 Operational impacts to surface water as a result of ERAs and widened slip roads have been considered in the design of the scheme as stated above. The overall operational impacts of this section of the M25 will be assessed as part of the Priority Outfalls scheme. As such, operational impacts of the ERAs and slip road widening on surface water are not assessed further. Surface water – construction 14.6.12 There may be impacts on surface water during construction, including potential for silt to be washed off earthworks (e.g. temporary stockpiles) and into watercourses and accidental spillage of fuels, lubricants or hydraulic oils from plant and storage areas. Groundwater - operation 14.6.13 As there are no direct discharges to groundwater for this scheme, additional runoff and potential spillages from the operation of the ERAs and widened slip roads are unlikely to interact with groundwater and the overall impacts to groundwater have been scoped out. 14.6.14 Local operational impacts on groundwater as a result of ERAs and widened slip roads have been considered in the design of the scheme. Existing drains will be retained where possible and any drainage that has to be removed will be reinstated in the verge or hard shoulder. Storage and pollution control to mitigate operational impacts on groundwater are also included in the design . As such, operational impacts of the ERAs and slip road widening on groundwater are not assessed further. Groundwater – construction 14.6.15 During the construction phase there is potential for contaminated site runoff and accidental spillages to interact with groundwater. There is a risk of intercepting contaminated land which could create a contaminant migration pathway to groundwater. These impacts are assessed in Chapters 9 and 10. Where there is a risk of groundwater being intercepted during construction, dewatering may be needed which would require Consent. 14.6.16 Run-off or accidental spillage during construction could affect groundwater directly. Floodplain – operation 14.6.17 Flood risk could be increased if there is an increase in runoff as a result of an increase in impermeable surface. However, increased volumes have been calculated and attenuation built into the design so this impact will not be assessed further. Removal of existing drainage could increase runoff. However, where existing drainage is to be removed it will be reinstated with a similar system in the hard shoulder or verge) and this will not be assessed further.
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14.6.18 Constriction of existing watercourses by culverting under ERAs or widened slip roads could also increase flood risk. However, the design does not include lengthening any culverts, so this impact is not assessed further. Floodplain – construction 14.6.19 Flood risk could be increased if ERAs are constructed or slip road widening takes place on floodplains as there is potential for loss of flood storage. However, at this stage the level of piling relative to flood levels at each of the ERAs is not known. Once this is known, further flood risk assessment may be required for ERAs in Flood Zones 2 and 3. Mitigation within Design 14.6.20 Mitigation measures for attenuation and water quality included in the scheme design are described above. 14.6.21 Mitigation for water quality impacts as a result of the operation of the whole road will be considered as part of the Priority Outfalls scheme. Enhancement Measures 14.6.22 No enhancement measures are proposed as part of this scheme. Monitoring Requirements 14.6.23 Water quality monitoring should not be required. Mitigation is being applied locally for each new ERA and slip road widening, so it would not be appropriate to illustrate these relatively small changes by monitoring receiving watercourses. This could be applied at the Priority Outfalls investigation when the overall road section will be assessed and potentially mitigated 14.7 Magnitude of Impacts (Change) Surface water 14.7.1 As described above, the assessment considers the impacts of construction of the scheme on surface water. Operational impacts are not being assessed as they are mitigated through design. The impact of construction of the scheme on surface water has been assessed using the methodology described in section 14.3. 14.7.2 It will be necessary to assess the potential impact of any site compounds that may be set up during the Scheme on surface water, once their location is known. ERAs 14.7.3 The magnitude of construction impacts on watercourses is summarised in Tables 14.10 and 14.11. The magnitude of impact is classified as high, medium or low, depending on proximity of the ERA to the watercourse. Table 14.10 - Magnitude of Construction Impact on Surface Water – ERAs, Clockwise Carriageway
ERA location Nearest watercourse Approximate Magnitude of (chainage) distance to impact watercourse (m)
40000 Tributary of Mimshall Brook1 >500 Low
40850 Tributary of Mimshall Brook >500m Low
43050 Turkey Brook 180 Medium
45200 Turkey Brook 70 High
46400 Cuffley Brook 420 Medium
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ERA location Nearest watercourse Approximate Magnitude of (chainage) distance to impact watercourse (m)
47500 Cuffley Brook >500 Low
53400 River Lee 240 Medium
54300 Cobbin‟s Brook 100 Medium
1 Nearest water course is on the other side of the carriageway. Further investigation would be required to determine if there is a pathway and magnitude of impact.
Table 14.11 - Magnitude of Construction Impact on Surface Water – ERAs, Anti-clockwise Carriageway
ERA location Nearest watercourse Distance to Magnitude of (chainage) watercourse (m) impact
40050 Tributary of Mimshall Brook >500 Low
42350 Turkey Brook2 110 Medium
44400 Turkey Brook2 80 High
46400 Cuffley Brook >500 Low
48150 Tributary of Cuffley Brook 165 Medium
54400 Cobbin‟s Brook2 105 Medium
57050 Tributary of Cobbin‟s Brook >500m Low
57750 Tributary of Cobbin‟s Brook 395 Medium
2 Nearest water course is on the other side of the carriageway. Further investigation would be required to determine if there is a pathway and magnitude of impact. Slip road widening 14.7.4 The magnitude of construction impacts on surface water as a result of slip road widening is summarised in Tables 14.2 and 14.13. The magnitude of impact is classified as high, medium or low, depending on proximity of slip road widening to the watercourse. Table 14.12 - Magnitude of Construction Impact on Surface Water - Slip Road Widening, Clockwise Carriageway
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Slip road widening Nearest watercourse Distance to Magnitude of location (chainage) watercourse at impact closest point (m)
37550 – 38600 Mimshall Brook 20 High
41000 – 41350 Turkey Brook >500 Low
55400 – 55850 Tributary of River Lee 150 Medium
59900 – 60450 Tributary of Cobbin‟s Brook 365 Medium
60900 – 61900 Brookhouse Brook 20 High
61950 - 62950 Brookhouse Brook 70 High
Table 14.13 - Magnitude of Construction Impact on Surface Water - Slip Road Widening, Anti- clockwise Carriageway
Slip road widening Nearest watercourse Distance to Magnitude of location (chainage) watercourse at impact closest point (m)
37750 – 38500 Mimshall Brook 20 High
41200 – 41350 Turkey Brook3 >500 Low
55400 – 56150 Cobbin‟s Brook 30 High
56650 – 56880 Beech Hill Brook >500 Low
59950 – 60450 Tributary of Brookhouse 225 Medium Brook
60900 - 61850 Brookhouse Brook 70 High
62400 – 62900 Brookhouse Brook >500 Low 3 Nearest water course is on the other side of the carriageway. Further investigation would be required to determine if there is a pathway and magnitude of impact.
Groundwater 14.7.5 The assessment considers the impacts of construction of the scheme on groundwater. Operational impacts are not being assessed as they are mitigated through design. The impact of construction of the scheme on groundwater has been assessed using the methodology described in section 14.3. 14.7.6 It will be necessary to assess the potential impact of any site compounds that may be set up during the Scheme on ground water, once their location is known. ERAs 14.7.7 The magnitude of impacts on groundwater from construction of ERAs is summarised in Tables 14.14 and 14.15. The magnitude of impact is classified as high, medium or low, depending on proximity of ERAs to source protection zones. Table 14.14 - Magnitude of Construction Impact on Groundwater – ERAs, Clockwise Carriageway
ERA location (chainage) Distance to nearest SPZ Magnitude of impact
40000 >1km Low
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ERA location (chainage) Distance to nearest SPZ Magnitude of impact
40850 >1km Low
43050 >1km Low
45200 >1km Low
46400 >1km Low
47500 >1km Low
53400 Within SPZ High
54300 50m High
Table 14.15 - Magnitude of Construction Impact on Groundwater – ERAs, Anti-clockwise Carriageway
ERA location (chainage) Distance to nearest SPZ Magnitude of impact
40050 >1km Low
42350 >1km Low
44400 >1km Low
46400 >1km Low
48150 >1km Low
54400 50m High
57050 >1km Low
57750 >1km Low
Slip road widening 14.7.8 The magnitude of impact on groundwater from the construction of slip road widening is summarised in Tables 14.16 and 14.17. The magnitude of impact is classified as high, medium or low, depending on proximity of the slip road widening to SPZs.
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Table 14.16 - Magnitude of Construction Impacts of Groundwater – Slip Road Widening, Clockwise Carriageway
Slip road widening location Distance to nearest SPZ Magnitude of impact (chainage)
37550 – 38600 250 Medium
41000 – 41350 >1km Low
55400 – 55850 >1km Low
59900 – 60400 >1km Low
60900 – 61900 >1km Low
61950 – 62950 >1km Low
Table 14.17 - Magnitude of Construction Impacts on Groundwater - Slip Road Widening, Anti- clockwise Carriageway
Slip road widening location Distance to nearest SPZ Relative sensitivity (chainage)
37750 – 38500 300 Medium
41200 – 41350 >1km Low
55400 – 56150 >1km Low
56650 – 56880 >1km Low
59950 – 60450 >1km Low
60950 - 61850 >1km Low
62400 – 62900 >1km Low
Floodplain 14.7.9 The assessment considers the impacts of construction of the scheme on the floodplain. Operational impacts are not being assessed as they are mitigated through design. The impact of construction of the scheme on the floodplain has been assessed using the methodology described above. The magnitude of impact of construction of ERAs and slip road widening depends on which Flood Zone the proposed features are in. ERAs 14.7.10 The magnitude of construction impacts on the floodplain associated with ERAs are summarised in Tables 14.18 and 14.19. Table 14.18 - Magnitude of Construction Impacts on Floodplain – ERAs, Clockwise Carriageway
ERA location (chainage) Flood Zone Magnitude of impact
40000 1 Low
40850 1 Low
43050 1 Low
45200 1 Low
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ERA location (chainage) Flood Zone Magnitude of impact
46400 1 Low
47500 1 Low
53400 2 Medium
54300 1 Low
Table 14.19 - Magnitude of Construction Impacts on Floodplain – ERAs, Anti-clockwise Carriageway
ERA location (chainage) Flood Zone Magnitude of impact
40050 1 Low
42350 1 Low
44400 1 Low
46400 1 Low
48150 1 Low
54400 1 Low
57050 1 Low
57750 1 Low
14.7.11 The majority of ERAs are in Flood Zone 1 and are will have a low impact on the floodplain. However, the ERA at chainages 53400 on the clockwise carriageway is in Flood Zone 2. The ERA in Flood Zone 2 may have an effect on flood storage. 14.7.12 All earthworks for ERAs will be accommodated by steel sheet piling (see ERA layout drawing in Figure 2.1). At embankments infilling required to accommodate the ERA could result in a loss of floodplain storage. The impact on storage will depend on the level of the piling in relation to flood levels. If the piling level and infill volume is above flood level, there will be no loss of storage. However, if the piling level and infill volume is below the maximum flood level of a 1 in 100 plus climate change year event, flood storage will be lost. At the current stage of design, this information is not available for specific ERAs. Once detailed designs have been developed for individual ERAs, further assessment will be required to determine the impact on flood storage as a result of constructing the ERA in Flood Zone 2. This will require consultation with the Environment
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Agency and a data request for flood level data should be made. Works within 8 meters of the top of the bank of a main river will also require consent from the Environment Agency. Slip road widening 14.7.13 The magnitude of construction impacts on the flood plain as a result of slip road widening are summarised in Tables 14.20 and 14.21. Table 14.20 - Magnitude of Construction Impacts - Slip Road Widening, Clockwise Carriageway
Slip road widening location Flood Zone Magnitude of impact (chainage)
37550 – 38600 1 Low
41000 – 41350 1 Low
55400 – 55850 1 Low
59900 – 60400 1 Low
60900 – 61900 1 Low
61950 - 62950 1 Low
Table 14.21 - Magnitude of Construction Impacts - Slip Road Widening, Anti-clockwise Carriageway
Slip road widening location Flood Zone Relative sensitivity (chainage)
37750 – 38500 1 Low
41200 – 41350 1 Low
55400 – 56150 1 Low
56650 – 56880 1 Low
59950 – 60450 1 Low
60950 - 61850 1 Low
62400 – 62900 1 Low
14.7.14 None of the slip road widening is to take place in a floodplain although the widening to the east of Junction 23 (chainage 37600 – 38600 clockwise and chainage 37750 – 38500 anti-clockwise) is close to the floodplain. Mitigation Operational impacts 14.7.15 Proposed mitigation for attenuation, water quality and flood risk was considered. As a result, operational impacts on surface water, groundwater and flood risk were not assessed further. No further mitigation for the scheme is recommended. 14.7.16 This assessment has only considered the impact of the managed motorways scheme and has not considered the effect of the existing road on the water environment. It is assumed that water quality mitigation that is required for the existing road will be considered as part of the Priority Outfalls scheme.
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Construction impacts 14.7.17 There is potential for the scheme to have an effect on surface and groundwater where ERAs and slip road construction takes place in close proximity to sensitive watercourses and groundwater. The potential impacts on the water environment can be mitigated through adherence to best practice pollution prevention. All areas of construction should follow best practice to avoid pollution of water assets, but particular attention should be given to those ERAs classified as “more” or “most significant”. 14.7.18 Relevant Pollution Prevention Guidance should be followed at all times during construction. As advised in the DMRB (HD45/09), action should be taken on: Bunding Routes of temporary traffic diversions Storage of hazardous wastes and materials Procedures for concreting Wash down areas and disposal of surface water runoff from excavations during construction. 14.7.19 Further guidance on actions to reduce the risk of pollution from construction activity is available in two CIRIA documents (Masters-Williams 2001 and Murname et al. 2006). 14.7.20 Particular care should be taken during the construction of the following features due to their proximity to watercourses of very high importance (see Section 14.4.4): ERA at chainage 45200 on the clockwise carriageway ERAs at chainage 44400 on the anticlockwise carriageway Slip road widening at chainages 37550 – 38600, 60900 - 61900 and 61950 – 62950 on the clockwise carriage way Slip road widening at chainages 37750 – 38500, 55400 – 56150 and 60950 - 61850 on the anti-clockwise carriageway. 14.7.21 Where there is a risk of groundwater being intercepted during construction, particularly at chainage 53400 on the clockwise carriageway and at chainage 54400 on the anti-clockwise carriageway, dewatering may be needed if groundwater is intercepted. This would require consent from the Environment Agency. 14.7.22 The ERA at chainage 53400 on the clockwise carriageway is in Flood Zone 2. The ERA in Flood Zone 2 may have an effect on flood storage. Further flood risk assessment should be carried out once detailed designs for this ERA is available. This will require consultation with the Environment Agency. If construction of the ERA will result in a loss of floodplain storage (and it cannot be re- located outside the floodplain), replacement storage must be provided, as set out in DMRB (HD45/09). This should be provided on a level for level, volume for volume basis in line with CIRIA C624 „Development & flood risk- guidance for the construction industry‟, or as agreed with the Environment Agency. Works within 8 meters of the top of the bank of a main river will also require consent from the Environment Agency.
14.8 Significant Effects 14.8.1 The significance of the effects of the scheme on the water environment has been assessed using the criteria above, see section 14.3.26. Significance of effects is determined by considering the importance of water attributes and the magnitude of impacts. For the purpose of this assessment, the classification of significance (most significant to insignificant) is a relative measure. The significance classification indicates the relative potential for an effect on water assets from construction of each ERA and length of slip road widening.
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Surface water 14.8.2 Tables 14.22 – 14.25 summarises the significance of effect of construction on watercourses in the study area.
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Table 14.22 - Significance of Construction Effects on Surface Water – ERAs, Clockwise Carriageway
ERA Nearest Importance of Magnitude of Significance location watercourse watercourse impact of effect
40000 Tributary of Mimshall Low Low Insignificant Brook1
40850 Tributary of Mimshall Low Low Insignificant Brook
43050 Turkey Brook Very high Medium More significant
45200 Turkey Brook Very high High Most significant
46400 Cuffley Brook Very high Medium More significant
47500 Cuffley Brook Very high Low More significant
53400 River Lee Low Medium Less significant
54300 Cobbin‟s Brook Very high Medium More significant
1 Nearest water course is on the other side of the carriageway. Further investigation would be required to determine if there is a pathway and magnitude of impact. Table 14.23 - Significance of Construction Effects on Surface Water – ERAs, Anti-clockwise Carriageway
ERA Nearest Importance of Magnitude of Significance location watercourse watercourse impact
40050 Tributary of Mimshall Low Low Insignificant Brook
42350 Turkey Brook2 Ver y high Medium More significant
44400 Turkey Brook2 Very high High Most significant
46400 Cuffley Brook Very high Low More significant
48150 Tributary of Cuffley Low Medium Less significant Brook
54400 Cobbin‟s Brook2 Very high Medium More significant
57050 Tributary of Cobbin‟s Low Low Insignificant Brook
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ERA Nearest Importance of Magnitude of Significance location watercourse watercourse impact
57750 Tributary of Cobbin‟s Low Medium Less significant Brook
2 Nearest water course is on the other side of the carriageway. Further investigation would be required to determine if there is a pathway and magnitude of impact.
Table 14.24 - Significance of construction effects on surface water - slip road widening, clockwise
Slip road Nearest Importance of Magnitude Significance widening watercourse watercourse of impact location
37550 – 38600 Mimshall Brook Very high High Most significant
41000 – 41350 Turkey Brook Very high Low More significant
55400 – 55850 Tributary of River Lee Low Medium Less significant
59900 – 60400 Tributary of Cobbin‟s Low Medium Less significant Brook
60900 - 61900 Brookhouse Brook Low Medium Less significant
61950 - 62950 Brookhouse Brook Low High Less significant
Table 14.25 - Significance of Construction Effects on Surface Water - Slip Road Widening, Anti- clockwise
Slip road Nearest Importance of Magnitude Significance widening watercourse watercourse of impact location
37750 – 38500 Mimshall Brook Very high High Most significant
41200 – 41350 Turkey Brook3 Very high Low More significant
55400 – 56150 Cobbin‟s Brook Very high High Most significant
56650 – 56880 Beech Hill Brook Low Low Insignificant
59950 – 6050 Tributary of Low Medium Less significant Brookhouse Brook
60950 – 61850 Brookhouse Brook Low High Less significant
62400 – 62900 Brookhouse Brook Low Low Insignificant
3 Nearest water course is on the other side of the carriageway. Further investigation would be required to determine if there is a pathway and magnitude of impact.
14.8.3 The most significant potential impacts on surface water occur where construction is to take place in close proximity to waterbodies with good water quality. This includes: ERA at chainage 45200 (Turkey Brook) on the clockwise carriageway ERA at chainage 44400 (Turkey Brook) on the anticlockwise carriageway Slip road widening at chainage 37550 – 38600 (Mimshall Brook) on the clockwise carriageway
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Slip road widening at chainages 37750 – 38500 (Mimshall Brook) 55400 – 56150 (Cobbin‟s Brook) on the anti-clockwise carriageway. 14.8.4 It will be necessary to assess the impact of any site compounds that may be set up during the Scheme on surface water, once their location is known. Groundwater 14.8.5 The significance of the impacts on groundwater depends on the importance of the attribute and the potential magnitude of impact. Tables 14.26 – 14.29 summarise the significance of construction impacts on groundwater in the study area. Table 14.26 - Significance of Construction Effects on Groundwater – ERAs, Clockwise
ERA Importance of Magnitude of Significance groundwater impact
40000 Low Low Insignificant
40850 Low Low Insiginficant
43050 Low Low Insignificant
45200 Low Low Insignificant
46400 Low Low Insignificant
47500 Low Low Insignificant
53400 Very high High Most significant
54300 Low High Less significant
Table 14.27 - Significance of Construction Effects on Groundwater – ERAs, Anti-clockwise
ERA Importance of Magnitude of Significance groundwater impact
40050 Low Low Insignificant
42350 Low Low Insignificant
44400 Low Low Insignificant
46400 Low Low Insignificant
48150 Low Low Insignificant
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ERA Importance of Magnitude of Significance groundwater impact
54400 Low High Less significant
57050 Low Low Insignificant
57750 Low Low Insignificant
Table 14.28 - Significance of Construction Effects on Groundwater - Slip Road Widening, Clockwise
Slip road widening Importance of Magnitude of Significance groundwater impact
37550 – 38600 Very high Medium More significant
41000 – 41350 Low Low Insignificant
55400 – 55850 Low Low Insignificant
59900 – 60400 Low Low Insignificant
6099 – 61900 Low Low Insignificant
61950 - 62950 Low Low Insignificant
Table 14.29 - Significance of Slip Road Widening Construction on Groundwater (anti-clockwise)
Slip road widening Importance of Sensitivity Significance groundwater
37750 – 38500 Very high Medium More significant
41200 – 41350 Low Low Insignificant
55400 – 56150 Low Low Insignificant
56650 – 56880 Low Low Insignificant
59950 – 60450 Low Low Insignificant
60950 - 61850 Low Low Insignificant
62400 – 62900 Low Low Insiginficant
14.8.6 The most significant impacts on groundwater are likely to occur where construction is to take place in close proximity to protected groundwater. This includes the ERAs at chainage 53400 on the clockwise carriageway. 14.8.7 It will be necessary to assess the impact of any site compounds that may be set up during the Scheme on ground water, once their location is known.
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Floodplain 14.8.8 The significance of the impacts on flood risk depends on the importance of the floodplain attribute and the magnitude of impact. Tables 14.30 – 14.33 summarise the significance of construction impacts on the floodplain in the study area. Table 14.30 - Significance of Construction Effects on Floodplain – ERAs, Clockwise Carriageway
ERA Importance of Magnitude of Significance floodplain impact
40000 Low Low Insignificant
40850 Low Low Insignificant
43050 Low Low Insignificant
45200 Low Low Insignificant
46400 Low Low Insignificant
47500 Low Low Insignificant
53400 High Medium More significant
54300 Low Low Insignficant
Table 14.31 - Significance of Construction Effects on Floodplain – ERAs, Anti-clockwise Carriageway
ERA Importance of Magnitude of Significance floodplain impact
40050 Low Low Insignificant
42350 Low Low Insignificant
44400 Low Low Insignificant
46400 Low Low Insignificant
48150 Low Low Insignificant
54400 Low Low Insignificant
57050 Low Low Insignificant
57750 Low Low Insignificant
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ERA Importance of Magnitude of Significance floodplain impact
Table 14.32 - Significance of Construction Effects on Floodplain - Slip Road Widening, Clockwise Carriageway
Slip road widening Importance of Magnitude of Significance floodplain impact
37550 – 38600 Low Low Insignificant
41000 – 41350 Low Low Insignificant
55400 – 55850 Low Low Insignificant
59900 – 60400 Low Low Insignificant
6900 – 61900 Low Low Insignificant
61950 - 62950 Low Low Insignificant
Table 14.33 - Significance of Slip Road Widening Construction on Flood Risk (anti-clockwise)
Slip road widening Importance of Magnitude of Significance floodplain impact
37750 – 38500 Low Low Insignificant
41200 – 41350 Low Low Insignificant
55400 – 56150 Low Low Insignificant
56650 – 56880 Low Low Insignificant
59950 – 60450 Low Low Insignificant
60950 - 61850 Low Low Insignificant
62400 – 62900 Low Low Insignificant
14.8.9 The majority of works under the scheme will take place in Flood Zone 1 where there is likely to be an insignificant effect on the floodplain. However, where ERAs are being constructed in Flood Zone 2 or 3, there may be an increase in flood risk due to potential loss of storage. The ERA at chainage 53400 on the clockwise carriageway is in Flood Zone 2. 14.8.10 Further assessment will be required to determine the impact on flood storage as a result of constructing this ERA in the floodplain once detailed design for the ERA is available. This will require a data request to the Environment Agency for flood level data. Works within 8 meters of the top of the bank of a main river require consent from the Environment Agency. Significance of Effects on Plans and Policies 14.8.11 The proposed drainage design does not include mitigation for the potential increase in flood risk caused by constructing the ERA at chainage 53400 on the clockwise carriageway in the floodplain. Further assessment is required to identify the significance of this effect and potential requirement for additional storage. Without such mitigation (if necessary), the scheme would not meet the requirements of PPS25 and a number of local policies. However, if additional storage is provided, the scheme should be compliant with PPS25 and the local policies regarding flood risk.
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14.8.12 The mitigation included in the design for attenuation and water quality should ensure the scheme complies with local policies regarding water quality and runoff 14.8.13 If pollution prevention guidance is followed during construction the scheme should be compliant with the policies listed in section 14.5. 14.9 Indication of Any Difficulties Encountered 14.9.1 This assessment has only considered the impact of the managed motorways scheme and has not considered the effect of the existing road on the water environment. 14.9.2 Operational impacts of ERAs and slip road widening were scoped out of the assessment due to mitigation measures included in design. The assessment has been limited to construction impacts on the water environment. It was therefore not possible to use the relevant criteria from the DMRB (HD45/09) to assess the impacts of the scheme. In order to assess the construction impacts of the MM scheme on the water environment, professional judgement was used. The overall assessment of the road section will be picked up by the Priority Outfalls investigation that is assessing impacts from all motorways and trunk roads. 14.9.3 There is potential for construction of ERAs in the floodplain to result in loss of floodplain storage. The impact on storage will depend on the level of the piling in relation to flood levels. At the current stage of design, this information is not available for specific ERAs. Once detailed designs have been developed for individual ERAs, further flood risk assessment will be required to determine the impact on flood storage as a result of constructing ERAs in Flood Zones 2 and 3. 14.10 Summary 14.10.1 Operational impacts of the whole road on water environment attributes have been scoped out of this assessment as they will be picked up by the Priority Outfalls investigation that is assessing the impacts from all motorways and trunk roads. Local operational impacts from the ERAs and slip road widening have been considered in the scheme design which includes mitigation measures. 14.10.2 The results of individual assessments of the construction effects of ERAs and slip road widening on the water environment are shown in the tables in section 14.9. The most significant effects highlighted by the assessment are summarised below. 14.10.3 The most significant construction effects impacts on surface water are likely to occur where construction is to take place in close proximity to waterbodies with good water quality. This includes: ERA at chainage 45200 (Turkey Brook) on the clockwise carriageway ERA at chainage 44400 (Turkey Brook) on the anticlockwise carriageway Slip road widening at chainage 37550 – 38600 (Mimshall Brook) Slip road widening at chainage 37750 – 38500 (Mimshall Brook) and 55400 – 56150 (Cobbin‟s Brook) on the anti-clockwise carriageway. 14.10.4 Potential construction impacts on surface water can be mitigated through following relevant Pollution Prevention Guidance (listed in section 14. 5). Extra care should be taken at the most sensitive locations listed above. 14.10.5 The most significant impacts on groundwater are likely to occur where construction is to take place in close proximity to protected groundwater. This includes: ERA at chainage 53400 on the clockwise carriageway.
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14.10.6 Potential construction impacts on groundwater can be mitigated through following relevant Pollution Prevention Guidance. Extra care should be taken at the most sensitive locations listed above. 14.10.7 It will be necessary to assess the potential impacts of any site compounds that may be set up during the Scheme on surface and groundwater, once their location is known. 14.10.8 Where construction is to take place in Flood Zone 2 , there may be an increase in flood risk due to potential loss of storage. The locations is: ERA at chainage 53400 on the clockwise carriageway. 14.10.9 Flood risk assessment should be carried out once detailed designs for ERAs in Flood Zone 2 and 3 are available. If construction of the ERAs will result in a loss of floodplain storage (and they cannot be re-located outside the floodplain), replacement storage must be provided. Works within 8 meters of the top of the bank of a main river require consent from the Environment Agency. 14.10.10 This assessment has only considered the impact of the managed motorways scheme and has not considered the effect of the existing road on the water environment. Mitigation for impacts on water environment attributes from the existing road will be considered as part of the Priority Outfalls scheme. 14.10.11 Mitigation described in section 14.7 will be followed, meaning that the overall construction effect of the MM scheme on water and drainage will be neutral. The overall operational effect of the MM scheme on water and drainage will also be neutral as mitigation is included in the design of ERAs and slip road widening. The overall effect of the proposed drainage scheme on the water environment will therefore be neutral.
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15. Assessment of Cumulative Effects 15.1 Introduction 15.1.1 Cumulative effects are the result of multiple actions on environmental receptors or resources. There are principally two types of cumulative effect to be assessed: Type 1 - where different environmental impacts are acting on a given receptor, but are the result of one project; or Type 2 - where environmental impacts are the result of multiple projects in combination (including the project being assessed). 15.2 Baseline Conditions 15.2.1 The cumulative assessment draws on baseline knowledge set out in the specialist environmental chapters of this report (Chapters 5 to 14), which is not repeated here. The principal receptor groups/types to which multiple effects relate comprise ecological receptors (flora/fauna – as identified in Chapter 8: Nature Conservation) and human/human centred receptors (as collectively represented by the properties identified in Chapters 5, 6, 7 and 11). These two receptor groups form the basis for the assessment of Type 1 effects. 15.2.2 Construction of the Project would be phased and is planned to commence in Spring 2014, with completion in 2015 (the opening year of the Project) and a Design Year of 2030. In order to determine Type 2 effects, the assessment has considered existing and reasonably foreseeable projects which are set out in Table 15.2 below. 15.3 Methodology 15.3.1 The cumulative environmental effects during construction and operation are considered against the significance criteria set out in DMRB Volume 11, Section 2, Part 5 (Table 2.6), as shown in Table 15.1: Table 15.1 - Significance Criteria - Cumulative
Significance Effect
Severe Effects that the decision-maker must take into account as the receptor/resource is irretrievably compromised.
Major Effects that may become a key decision-making issue.
Moderate Effects that are unlikely to become issues on whether the project design should be selected, but where future work may be needed to improve on current performance.
Minor Effects that are locally significant.
Not Significant Effects that are beyond the current forecasting ability or are within the ability of the resource to absorb such change.
15.3.2 These criteria could reflect beneficial or adverse effects, although the nature of cumulative effects means they are more likely to be considered adverse.
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15.4 Cumulative Effects of the Project (Type 1) 15.4.1 This section identifies where receptors may experience multiple effects resulting from different environmental impacts, referring to the specialist environmental chapters of this report (Chapters 5 to 14) where appropriate. Construction 15.4.2 Cumulative effects on ecological receptors are identified in detail within Chapter 8: Nature Conservation. In summary, the combination of dust (Chapter 5: Air Quality), risk of pollution (Chapter 14: Road Drainage and the Water Environment, Chapter 9: Geology and Soils, and Chapter 10: Materials), and noise disturbance (Chapter 11: Noise) effects are most likely to result in cumulative effects during construction, however cumulative effects are anticipated to be localised and of Minor Significance (Adverse). 15.4.3 In the case of human receptors, properties which are in the vicinity of proposed gantries and cantilever signs, are those where the greatest adverse visual effects are anticipated during construction (refer to Chapter 7: Landscape). There are no significant built heritage effects anticipated as proposed changes are assessed in the context of the existing road (refer to Chapter 6: Cultural Heritage). Whilst construction noise and dust effects on properties are not assessed in detail at this stage (Chapter 11: Noise, and Chapter 5: Air Quality, respectively), effects are likely to vary temporally at any given location, as construction activities change across the site, such that cumulative effects at any given location would be limited. Taking these considerations into account, overall cumulative effects are assessed to be of Minor Significance (Adverse). 15.4.4 Overall Type 1 cumulative effects during construction are assessed to be of Minor Significance (Adverse). Operation 15.4.5 Cumulative effects on ecological receptors are identified in detail within Chapter 8: Nature Conservation. In summary, the existing situation with respect to ecological receptors would remain largely unchanged with the receptors near to the M25 already habituated to environmental conditions such as noise levels (Chapter 11: Noise), air quality conditions (Chapter 5: Air Quality) and road drainage (Chapter 14: Road Drainage and the Water Environment), such that cumulative effects are assessed to be Not Significant. 15.4.6 In terms of human receptors, properties which are in the vicinity of proposed gantries and cantilever signs, are those where the greatest adverse visual effects are anticipated during operation (Chapter 7: Landscape). There are no significant built heritage effects anticipated as proposed changes are assessed in the context of the existing road (Chapter 6: Cultural Heritage). The noise effects (Chapter 11: Noise) show that minor increases in noise would be experienced at residential and other sensitive receivers when the scheme opens. By the design year, and as a result of routine surfacing with lower noise surfaces there would be minor and moderate decreases in noise. In the case of air quality (Chapter 5: Air Quality), a negligible effect is predicted resulting from the Project. Slight adverse impacts, in relation to very small increases in NO2 concentrations, would coincide with the adverse visual impacts at Potters Bar (Receptors R25, Figure 5.2; and P13, Figure 7.4) and Waltham Cross (Receptors R42, Figure 5.2; and P34, Figure 7.4). In the case of the Potters Bar receptors, NO2 levels would remain below the EU Standard; in the case of the Waltham Cross NO2 levels would remain above the EU Standard. Overall, cumulative effects would be limited and localised and therefore of Minor Significance (Adverse). 15.4.7 Overall Type 1 cumulative effects during operation are assessed to be of Minor Significance (Adverse).
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15.5 Cumulative Effects of Multiple Projects (Type 2) 15.5.1 Cumulative effects may occur due to the various planned transportation and land development schemes in the vicinity of the Project. Known major planned developments that may contribute to cumulative effects have been included in Table 15.2 below. The noise and air quality assessments are based on a traffic model that includes all relevant existing and proposed major transport improvements in the area. Overall, potential cumulative effects during construction are assessed to be of Minor Significance (Adverse), and operational effects are assessed to be Not Significant. The cumulative effects of any additional projects should be considered when they are known. 15.6 Summary 15.6.1 In summary, Type 1 cumulative effects, or the combination of different environmental impacts acting on a given project receptor, are assessed to be of Minor Significance (Adverse) during construction and operation. Potential cumulative effects of multiple projects, or Type 2 cumulative effects, are assessed to be of Minor Significance (Adverse) during construction and Not Significant during operation. Table 15.2 - Known Major Planned Developments Scheme Description Programme Cumulative Impacts Highways Agency Planned Schemes M25 Junctions 16-23 Widening of existing dual Construction It is assumed that Widening three lane motorway to started 2009 construction will be dual four lanes. Operational complete prior to from 2012 construction of the Project. This EAR has considered the operational effects as part of the baseline for assessment, where appropriate. There are unlikely to be significant cumulative effects. M25 Junctions 27-30 Widening of existing dual Construction It is assumed that Widening three lane motorway to started 2009 construction will be dual four lanes. Operational complete prior to from 2012 construction of the Project. This EAR has considered the operational effects as part of the baseline for assessment, where appropriate. There are unlikely to be significant cumulative effects. M25 Junctions 26-27 Electrical/mechanical Refurbishment It is assumed that Tunnel Refurbishment refurbishment; walkway started 2008 construction will be removal. Operational complete prior to from 2010 construction of the Project. This EAR has considered the operational effects as part of the baseline for assessment, where appropriate. There are unlikely to be significant cumulative effects.
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Scheme Description Programme Cumulative Impacts M25 Junction 30 Junction capacity Programme The programme is Improvements improvements uncertain. uncertain. Cumulative effects in conjunction with the Project are beyond current forecasting ability. M25 Junctions 5-7 Widening of existing dual Construction to This EAR has considered Managed Motorway three lane motorway to start 2013 the construction/operational dual four lanes. Operational effects as part of the from 2015 baseline for assessment, where appropriate. There are unlikely to be significant cumulative effects. M25 Junctions 7-10 Gantry upgrades. J7-J8 complete This EAR has considered Gantry Upgrade in 2011 the construction/operational Programme for effects as part of the J8 – J10 baseline for assessment, uncertain. where appropriate. There are unlikely to be significant cumulative effects. M11 Junctions 6-8 Road improvements. Programme The programme is Improvements uncertain. uncertain. Cumulative effects in conjunction with the Project are beyond current forecasting ability. M11 and A120 New M11 and A120 Programme The programme is Stansted Airport junctions. uncertain. uncertain. Cumulative Access effects in conjunction with the Project are beyond current forecasting ability. Second Essex Local Transport Plan (LTP3) 2011 Stansted Airport New runway. Permission has The programme is Expansion been granted for uncertain.There are unlikely North of M25 Junction increasing to be significant cumulative 27 passenger effects in relation to numbers but the operation. application for a new runway has been withdrawn. Programme uncertain; Hertfordshire Local Transport Plan 2006/07 – 2010/11 Croxley Rail Link New rail line, Croxley to In planning, The programme is East of M25 Watford. programme uncertain; if operational by Junction 18 uncertain; A 2015 potential for minor decision will be cumulative effects during made in construction. There are December 2011 unlikely to be significant on funding. cumulative effects in relation Potentially to operation. operational by 2015
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Scheme Description Programme Cumulative Impacts Other Major Projects News International Part of the site remains Programme The programme is Site Redevelopment to be developed for uncertain. uncertain. Cumulative M25 Junction 25 business use, with effects in conjunction with required alterations to the Project are beyond M25 Junction 25. current forecasting ability. Crossrail New railway route Construction Potential for minor Near M25 Junction 28 through London (West- starts 2010 construction cumulative East) via Heathrow, Operational effects. The Crossrail Paddington, Liverpool 2017. Scheme could contribute to Street, Whitechapel and a reduction in the amount of Abbey Wood. operational traffic due to the potential for transfer of road users to rail transportation; however assessment of these effects is beyond current forecasting ability. Shell Haven Port Port development, Phased The programme is Development including M25 Junction development; uncertain. Cumulative Near M25 Junctions improvements. Programme effects in conjunction with 29-31 uncertain. the Project are beyond current forecasting ability. M25 Junctions 9 & 10 New Motorway Service Construction It is assumed that Motorway Service Area. starts 2010 construction will be Area Operational complete prior to 2012. construction of the Project. This EAR has considered the operational effects as part of the baseline for assessment, where appropriate. There are unlikely to be significant cumulative effects.
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16. Conclusions 16.1 Summary of Significant Effects 16.1.1 This EAR has provided an environmental assessment on the potential effects resulting from construction and operation of the Project. A summary of the main environmental effects for each topic is provided in Table 16.1 below. Table 16.1 - Summary of Significant Effects Significant Effects Overall Significance of Effects Air Quality Negligible In terms of construction, with mitigation measures in place (these would be implemented on the construction site and not at individual receptors), the risk during construction would be low risk. Construction would therefore be unlikely to cause a statutory nuisance. The local air quality assessment illustrates that there were no predicted modelled exceedances of the annual average NO2 EU Limit Value in the DS or the DM scenarios. The local air quality assessment illustrates that there would be no predicted modelled exceedances of the annual average PM10 EU Limit Value or permitted number of 24 hour mean exceedances in the DS. The regional assessment indicates that there would an increase in emissions with the scheme in 2015 and 2030 compared to the DM. Estimated concentrations of annual mean NOx at the Designated Sites: Epping Forest SAC, Epping Forest SSSI and Curtismill Green SSSI exceed the 30 µg/m3 Critical Level for the protection of vegetation in 2008 and 2015. With mitigation there are no predicted increases in NOx concentrations greater than or equal to 2 μg/m3 as a result of the scheme. The results of the air quality assessment for Designated Sites have been passed on to the project ecologist for inclusion in the ecological impact assessment. The overall impact of the scheme has been determined by the air quality assessments which indicate a negligible effect on air quality, with no exceedances of the EU Limit Values for NO2 and PM10 with the scheme. Cultural Heritage Slight Adverse The Project is likely to have a slight adverse effect on designated heritage assets including a slight adverse effect on three Grade II Listed Buildings, one Conservation Area and one Grade II* Registered Park and Garden. The majority of the c. 55 designated heritage assets within the study area will not be affected by the proposals. Landscape Slight Adverse The effects of the Project on landscape character and visual amenity on the majority of resource / receptors in the study area are generally Neutral or Slight Adverse due to the location of all proposed work within the existing M25 highway boundary and the restricted nature of the works. The Project would, however, result in a minor increase in visual intrusion and a slight increased perception of urbanisation in the countryside resulting from the proposed gantries. Overall the Project would have a Slight Adverse effect on landscape and visual amenity. Nature Conservation Slight Adverse There would be no long term impacts on designated sites although there would be a risk of a slight adverse effect during construction on Epping Forest SAC/SSSI but this is not considered significant. Any risk of potential impacts on designated watercourses and other watercourses would be reduced by use of appropriate pollution prevention measures and covered in the Construction Environmental Management Plan (CEMP). During the construction phase there would be a neutral effect on habitats of
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Significant Effects Overall Significance of Effects negligible value within the soft estate and their associated protected species. Potential effects on protected species would be reduced by appropriate seasonal timing of works, translocation, and ecological watching brief, habitat enhancement and creation, where appropriate. Where required, protected species licences will be obtained prior to works. The construction phase impacts of the scheme are considered to be slight adverse on great crested newts. The impact on this species will be reduced by appropriate mitigation measures, including those to be covered by EPS licensing. Overall the scheme is considered to have a „slight adverse‟ effect on ecological resources resulting from loss and severance of negligible value habitat within the soft estate and reduction of buffering of adjacent designated sites and severance of habitat within the HA soft estate that, although itself is of negligible value, contributes to the habitat of protected species, but this is not considered significant. A separate assessment (AIES) has concluded that this scheme does not result in a risk of likely significant effects on any Natura 2000 sites and therefore does not require „Appropriate Assessment‟. Geology and Soils Neutral The Project would not have a significant effect upon the geology and soils within the Study Area. There are no designated geological or geomorphological sites, active mines, quarries or active landfills within the Study Area. Local agricultural soil is classified as grade 3 or 4. However, a major aquifer and source protection zone means there is high importance or hydrogeology. During both construction and operation phases, a Neutral effect would be experienced on geology and soils attributes. Materials Slight Adverse Disruption due to construction would be minimised through implementation of the CEMP and SWMP. This would ensure construction activities complied with the requirements of environmental legislation and minimise waste arising from the works. The motorway would remain open during construction although traffic speeds would be reduced. A Slight Adverse effect would be experienced during construction. Historic landfill areas located in close proximity to the Project would require further assessment to determine the impacts of construction on harmful gases associated with landfills. Implementation of the CEMP would mitigate most significant effects to a Neutral to Slight Adverse effect. Noise Opening Calculations for the detailed study area show that on scheme opening, Slight Adverse approximately 3% of receptors are predicted to experience a minor change in noise, with the majority of receptors predicted to experience a negligible, or no Design Period change, in noise. By the design year, no receptors are expected to experience a Neutral perceptible increase in noise. A number of increases are predicted on routes within the wider area, these increases are predicted to occur both with and without the scheme, and therefore are not direct impacts of the scheme. The construction works required for the scheme may give rise to short term significant adverse impacts, particularly for works near residential properties, or works taking place at night. Such impacts may be limited by the use of Best Practicable Means. Overall there would be a slight adverse effect on scheme opening that would reduce to neutral after 15 years. Effects on All Travellers Neutral The Project will result in a slight adverse effect on views from the road, resulting in a slight adverse effect on travellers‟ views.
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Significant Effects Overall Significance of Effects Traffic forecasts show that traffic volumes are expected to increase in 2030 compared to existing conditions, either with or without the Project. The Project will help to alleviate uncertainty of routes and improve driver comfort, therefore having a Slight Beneficial effect upon driver stress. Overall the Project would have a neutral effect on all travellers. Community and Private Assets Neutral The Project is located entirely within SoS owned land, so any impacts upon private property, industrial land, community land use, community facilities, development land and agricultural resources would be negligible. There would be no community severance resulting from the Project. National policies for promoting improvements to the existing road network and freight corridor would be helped by the Project. Air quality policies would be only slightly affected by the Project, resulting in a negligible effect. A slight adverse effect would occur relating to landscape and nature conservation policies. A neutral effect would occur upon most other environmental policies. Road Drainage and the Water Environment Neutral The most significant construction effects impacts on surface water are likely to occur where construction is to take place in close proximity to waterbodies with good water quality. The most significant impacts on groundwater are likely to occur where construction is to take place in close proximity to protected groundwater. Where construction is to take place in Flood Zone 2 or 3, there may be an increase in flood risk due to potential loss of storage. The assessment has only considered the impact of the managed motorways scheme and has not considered the effect of the existing road on the water environment. It is known from the Stage 2 EAR (2010) that the quality of runoff from the existing road is, in many places, below current standards as defined by DMRB. Mitigation for impacts on water environment attributes from the existing road will be considered as part of the Priority Outfalls scheme. Cumulative Effects Minor Type 1 cumulative effects, or the combination of different environmental impacts Significance acting on a given project receptor, are assessed to be of Minor Significance (Adverse) (Adverse) during construction and operation. Potential cumulative effects of multiple projects, or Type 2 cumulative effects, are assessed to be of Minor Significance (Adverse) during construction and Not Significant during Operation. 16.2 Summary of Mitigation Measures 16.2.1 This EAR has provided an environmental assessment of MM ALR. Outside of that required for effective operation of MM ALR,the Project only includes the minimum improvements to the road superstructure (e.g. surfacing, vehicle restraint systems, environmental mitigation and drainage improvements) that would be required to achieve safe and legal operation. 16.2.2 The environmental assessment is based upon minimum improvements. However, the mitigation measures set out in 16.2.3 16.2.4 16.2.5 Table 16.2 have been incorporated into the assessments as these were deemed necessary to effectively and legally operate the Project. These mitigation measures were taken into consideration when determining the significance of effects summarised in Table 16.1.
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Table 16.2 - Summary of Mitigation Measures Description of Mitigation Measures Air Quality Mitigation measures for the control of dust during construction have been suggested. Implementation of a CEMP would be a mandatory requirement for the DBFO Contractor. With the operation of the Project, there would be no exceedances of any pollutants assessed within the Study Area and therefore no other mitigation is required. For the purpose of future air quality assessments there may be a requirement to update 2004 Base Year traffic data to the current year. Cultural Heritage No areas of known high archaeological sensitivity were identified during the desk study, but if they are identified at a later date adjustments to the detailed Project design would be proposed, where feasible. E.g. changes to foundation design or gantry/ERA location). Preservation in situ is the preferred mitigation to permanently protect and retain resources. Visual impacts from the Project on built heritage and designated historic landscapes would be mitigated through adjustments to the detailed Project design, where feasible. For example, movement of a gantry location. In cases where this is not feasible, built heritage receptors could be successfully mitigated through placement of appropriate screening. Landscape Specific mitigation measures to reduce adverse effects include new or strengthened planting at ERA‟s and gantries where existing screening is limited.In addition to these mitigation measures, best practice will be followed including: Ensuring loss of vegetation is minimised through good construction practices. Ensure protection of retained vegetation within the boundary in accordance with best practice and BS: 5837. Ensure all woodland adjacent to the highway boundary, including any ancient woodland, is protected in accordance with BS: 5837
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Description of Mitigation Measures Nature Conservation General construction impacts would be addressed by implementation of the CEMP, including an Ecological Management Plan. Advanced ecological works would be required prior to commencement of construction – these include vegetation clearance, protective fencing. Preparation of receptor sites may be required, which would be determined by a suitably qualified ecologist prior to the relocation/translocation of any species and relocation or translocation of protected or notable species. Licences should be obtained from Natural England, as appropriate, for works to proceed. Habitat loss should be kept to a minimum and encroachment onto adjacent habitat should be avoided by accurately fencing the works area. Location of Japanese Knotweed stands will need to be compared with the precise locations of gantries and refuge areas. Advance works would need to be implemented to control and remove this species to prevent spreading where Japanese Knotweed is located within 7m of the working area. Removal of rhizomes and safe disposal under licence by a specialist contractor should then be carried out. Part of the area supporting Yellow Vetchling will be lost with the Project. In order to prevent encroachment into the area of Yellow Vetchling that will be retained, the works area should be clearly demarcated with protective fencing. Following construction, the areas of disturbed ground which previously formed the works area should be sown with less vigorous grasses and with Yellow Vetchling seed collected from elsewhere in this area, in order to reinstate this species. Prior to the commencement of any works, a strategy for dealing with suitable great crested newt terrestrial habitat removal would be determined and agreed with Natural England. The need for advanced mitigation would be reviewed within the Project area where the presence of great crested newts is confirmed within 500 metres of an area subject to works activity. The need for mitigation associated with the installation of ERAs, gantries and cantilevers, would be reviewed on a site- specific basis. Reptile capture relocation operation would be undertaken, specifically in the area to be directly affected by minor widening to four lanes on the approaches to the tunnel portals. The extent of the mitigation should be informed by detailed surveys of the soft estate in this location, which would determine the size of the population and the species present. The identification of a suitable receptor site would also be necessary. Capture and relocation of reptiles should be undertaken either during April/May or September/October. Liaison with Natural England would be maintained throughout the process. Any vegetation clearance of suitable breeding bird habitat should be undertaken outside of the bird breeding season which extends between the end of February and mid-August, inclusive. Depending upon the detailed proposals, it may be appropriate to undertake further surveys of the two mature trees within the area to be affected by the four-lane widening, to confirm the presence or absence of roosting bats. Similarly, the need for surveys of the four trees within the HSR area should be reviewed, and should be undertaken if these trees are directly affected by the proposals. The appropriate mitigation would depend on the numbers and species of bats present. Factors such as floodlighting during the construction phase and vibration should be strictly controlled. Baffles should be used where necessary to reduce light spill from construction floodlights, as this may affect flight lines used by commuting and foraging bats. Exclusion fencing should be erected to avoid any inadvertent damage or disturbance to badger Sett 1. In addition, a careful search should be undertaken of any dense areas of scrub directly affected by the proposals, in order to confirm the absence of badger setts. The need for, and details of specific enhancement and compensation measures for bats, great crested newt and reptiles would be established following more detailed survey work for these species. Geology and Soils Geotechnical solutions are proposed for the Project, including reinforced soil blocks at the toe of cuttings, reinforced soil slopes, and regrading of slope angles. Where no soft solutions are available, retaining walls are proposed. In some locations it is suggested to remove alluvial deposits to avoid slope failure. Implementation of the CEMP would mitigate impacts upon geology and soils attributes.
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Description of Mitigation Measures Materials Implementation of a CEMP would be a mandatory requirement for the DBFO Contractor. The CEMP would include a Travel Plan, Landscape Management Plan, Ecological Management Plan and SWMP. The earthworks strategy will be to maximise re-use of material, minimise import and export of material, and minimise disposal of waste in landfill. Gantry foundations are likely to be up to 10 metres and piled. A site investigation would be required to confirm the location of made ground, landfill areas, material strength and suitability of soils and London Clay. In the Lea Valley area detailed ground investigation is required, in particular as the London Clay is likely to thin in this area providing less protection to groundwater. Noise There may be a small number of properties eligible for noise insulation. It is important to note that this assessment is indicative only and that a full noise insulation assessment should be carried out in full prior to the project opening. Effects on All Travellers General traffic management and CEMP measures would mitigate effects during the construction period. Community and Private Assets No mitigation measures are proposed for Community and Private Assets. Road Drainage and the Water Environment No new mitigation provision is intended on the Project for either the pollution impact associated with routine runoff or accidental spillage. No enhancement measures for water quality or runoff quality will be provided. Cumulative Effects No mitigation measures are proposed for Cumulative Effects.
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17. References Chapter 1 – Introduction Department for Transport (2002): London Orbital Multi-Modal Study. DfT Department for Transport (2008): Advanced Motorway Signalling and Traffic Management Feasibility Study. DfT Highways Agency (2008): Reporting of Environmental Impact Assessments -Design Manual for Roads and Bridges. Volume 11, Section 2, Part 6 Highways Agency (2009): Assessment of Implications (of Highways and/or Roads Projects) on European Sites (Including Appropriate Assessment) -Design Manual for Roads and Bridges. Volume 11, Section 4, Part 1 Chapter 2 – The Project Department for Transport (2002): London Orbital Multi-Modal Study. DfT Department for Transport (2008): Advanced Motorway Signalling and Traffic Management Feasibility Study. DfT Highways Agency (2007): M25 Widening Section 5 (Junction 23 to 27) Environment Assessment Report. Highways Agency (2007): M25 Widening Section 5 (Junction 23 – 27) Addendum Report Highways Agency (2008): M25 Managed Motorways Section 5 (Junction 23 – 27) Environmental Support Document Chapter 3 – Alternatives Considered Department for Transport (2008): Advanced Motorway Signalling and Traffic Management Feasibility Study. DfT Highways Agency (2008): M25 Managed Motorways Section 5 (Junction 23 – 27) Environmental Support Document Chapter 4 – Environmental Impact Assessment Methodology Highways Agency (2008): Environmental Assessment Techniques - Design Manual for Roads and Bridges. Volume 11, Section 2, Part 5 Highways Agency (2009): Managed Motorways Section 5 (Junction 23 – 27) Environmental Assessment Scoping Report Chapter 5 – Air Quality Ref. 5.1 - Highways Agency (2007): Air Quality - Design Manual for Roads and Bridges, Volume 11, Section 3, Part 1 (HA207/07). Available at http://www.dft.gov.uk/ha/standards/dmrb/vol11/section3/ha20707.pdf Ref. 5.2 - DEFRA (2007): The Air Quality Strategy for England, Scotland, Wales and Northern Ireland. Available at http://archive.defra.gov.uk/environment/quality/air/airquality/strategy/ Ref. 5.3 - EU: Directive 2008/50/EC of the European Parliament and of the Council of 21 May 2008 on ambient air quality and cleaner air for Europe. Available at http://eur- lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:32008L0050:en:NOT Ref. 5.4 - South Buckinghamshire District Council – Air Quality Review and Assessment Information, Available at http://www.southbucks.gov.uk/environment planning/pollution/air pollution and air quality/air quality revie w assessment.aspx
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Ref. 5.5 - Chiltern District Council – Air Quality Management Information Available at http://www.chiltern.gov.uk/CLAIRE Ref. 5.6 - Three Rivers District Council: Local Air Quality Management information. Available at: http://www.threerivers.gov.uk/Default.aspx/Web/AirQuality Ref. 5.7 - Dacorum Borough Council: Local Air Quality Management information. Available at: http://www.dacorum.gov.uk/default.aspx?page=1597 Ref. 5.8 - St Albans City and District Council: Local Air Quality Management information. Available at: http://www.stalbans.gov.uk/environment-and-planning/pollution/air-pollution/ Ref. 5.9 - Hertsmere Borough Council: Local Air Quality Management information. Available at: http://www.hertsmere.gov.uk/environmentplanning/pollution/pollutionair.jsp Ref. 5.10 – London Borough of Barnet: Local Air Quality Management. Available at http://www.barnet.gov.uk/info/940140/review and assessment of air quality/592/review and assessment of air quality Ref. 5.11 - Welwyn Hatfield Borough Council: Local Air Quality Management information. Available at: http://www.welhat.gov.uk/index.aspx?articleid=281 Ref. 5.12 - Broxbourne Borough Council: Local Air Quality Management information. Available at: http://www.broxbourne.gov.uk/environment and planning/pollution/pollution control-air quality.aspx Ref. 5.13 - London Borough of Enfield: Local Air Quality Management information. Available at: http://www.enfield.gov.uk/info/413/pollution control-air quality/333/pollution control air quality Ref. 5.14 - Epping Forest District Council: Local Air Quality Management information. Available at: http://www.eppingforestdc.gov.uk/council services/environmental health/pollution.asp Ref. 5.15 - Harlow Council: Local Air Quality Management information. Available at: http://www.essexair.org.uk/AQInEssex/LA/Harlow.aspx?View=reports&ReportType=HARLOW Ref. 5.16 – Uttlesford District Council: Local Air Quality Management information. Available at: http://www.essexair.org.uk/AQInEssex/LA/Uttlesford.aspx Ref. 5.17 - London Borough of Havering: Local Air Quality Management information. Available at: http://www.havering.gov.uk/Pages/Pollutioncontrolairquality.aspx Ref. 5.18 - Brentwood Borough Council: Local Air Quality Management information. Available at: http://www.brentwood.gov.uk/index.php?cid=399 Ref. 5.19 – Thurrock Council: Local Air Quality Management information. Available at: http://www.thurrock.gov.uk/environment/pollution/content.php?page=local air quality
Ref. 5.20 - DEFRA: NO2 diffusion tube bias adjustment factors. Available at http://laqm.defra.gov.uk/bias- adjustment-factors/bias-adjustment.html Ref. 5.21 - DEFRA: Background mapping. Available at http://laqm.defra.gov.uk/review-and- assessment/tools/background-maps.html Ref 5.22 - DEFRA: Background mapping methodology. Available at http://laqm.defra.gov.uk/maps/maps2008.html#anch2 Ref. 5.23 - Air Pollution Information System (APIS). Available at http://www.apis.ac.uk/ Ref. 5.24 - UNECE: Definitions of Critical Level and Critical Load. Available at http://www.unece.org/env/Irtap/WorkingGroups/wge/definitions.htm Ref. 5.25 - DEFRA (2009): Local Air Quality Management, Technical Guidance LAQM.TG(09). Available at http://www.defra.gov.uk/publications/2011/03/25/pb13081-laqm-technical-guidance-tg09/ Ref. 5.26 - TAG Unit 3.3.3 The Local Air Quality Sub-Objective, August 2012 [Online] Available at http://www.dft.gov.uk/webtag/documents/expert/unit3.3.3.php
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Ref. 5.27 - DEFRA: Emission factor toolkit. Available at http://laqm.defra.gov.uk/review-and- assessment/tools/emissions.html Ref. 5.28 - CERC: ADMS Roads. Available at http://www.cerc.co.uk/ Ref. 5.29 - Graz University of Technology Institute for Thermal Combustion Engines and Thermodynamics: GRAL and GRAMM. Available at http://www.ivt.tugraz.at/
Ref. 5.30 - DEFRA: NOx to NO2 calculator. Available at http://laqm.defra.gov.uk/review-and- assessment/tools/tools.html Ref. 5.31 - The Highways Agency position on local air quality. Available at: http://www.highways.gov.uk/knowledge/18550.aspx Ref. 5.32 - Highways Agency, Technical Review Paper „Review of the Highways Agency‟s Approach to Evaluating Significant Air Quality Effects‟, 7 September 2012 (available on request) Ref. 5.33 – HMSO: Environment Act 1995, c.25. Available at http://www.legislation.gov.uk/ukpga/1995/25/contents Ref. 5.34 - HMSO: The Air Quality (England) Regulations 2000 No. 928. Available at http://www.legislation.gov.uk/uksi/2000/928/contents/made Ref. 5.35 - HMSO: The Air Quality (England) (Amendment) Regulations 2002 No. 3043. Available at http://www.legislation.gov.uk/uksi/2002/3043/contents/made Ref. 5.36 - DEFRA (2009): Local Air Quality Management, Policy Guidance LAQM.PG(09). Available at http://www.defra.gov.uk/environment/quality/air/air-quality/laqm/guidance/policy/ Ref. 5.37 - HMSO: The Air Quality Standards Regulations 2010 No. 1001. Available at http://www.legislation.gov.uk/uksi/2010/1001/contents/made Ref. 5.38 - Natural England: Biodiversity 2020 Strategy. Available at http://www.naturalengland.org.uk/ourwork/conservation/biodiversity/protectandmanage/englandbiodiversityst rategy.aspx Ref. 5.39 - Highways Agency Sustainable development plan 2012 - 2015 'Positive about the future'. Available at http://www.highways.gov.uk/about-us/sustainability/sustainable-development/ Ref. 5.40 – DCLG: National Planning Policy Framework, March 2012 [Online] Available at http://www.communities.gov.uk/planningandbuilding/planningsystem/planningpolicy/planningpolicyframework / Ref. 5.41 - Government Office for the East of England, East of England Plan, May 2008. Available at http://webarchive.nationalarchives.gov.uk/20100528142817/http://gos.gov.uk/goeast/planning/regional plan ning/?a=42496 Ref. 5.42 - Greater London Authority, The London Plan Spatial Development Strategy for Greater London, July 2011. Available at http://www.london.gov.uk/thelondonplan/ Ref. 5.43 - Greater London Authority, Clearing the air - The Mayor‟s Air Quality Strategy December 2010. Available at http://www.london.gov.uk/publication/mayors-air-quality-strategy Ref. 5.44 - Greater London Authority and London Councils, The control of dust and emissions from construction and demolition Best Practice Guidance, November 2006. Available at http://www.london.gov.uk/thelondonplan/guides/bpg/bpg 04.jsp Ref. 5.45 - Buckinghamshire County Council, Buckinghamshire Local Transport plan 2011 – 2016, 2011. Available at http://www.tfbucks.co.uk/documents/ltp/LTP3.pdf Ref. 5.46 - Hertfordshire County Council, Hertfordshire Local Transport plan 2011-2031, April 2011. Available at http://www.hertsdirect.org/services/transtreets/transplan/ltp/ Ref. 5.47 - The Hertfordshire Air Quality Management Plan ,Hertfordshire County Council, 2009
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Ref. 5.48 - Essex County Council, Essex Transport Strategy the Local Transport Plan for Essex, June 2011. Available at http://www.essex.gov.uk/Environment%20Planning/Planning/Transport-planning/Pages/Local- transport-plan.aspx Ref. 5.49 - Planning and Compulsory Purchase Act 2004 c.5. Available at http://www.legislation.gov.uk/ukpga/2004/5/contents Ref. 5.50 - South Bucks District Council, Local Development Framework Core Strategy, 2011. Available at http://www.southbucks.gov.uk/includes/documents/cm docs/2011/s/sbdccorestrategy.pdf Ref. 5.51 - South Buckinghamshire District Council Consultation Draft Air Quality Action Plan-March 2006, Available at http://www.southbucks.gov.uk/environment planning/pollution/air pollution and air quality/air quality revie w assessment.aspx Ref. 5.52 - Chiltern District Council, Local Development Framework Core Strategy, 2011. Available at http://www.chiltern.gov.uk/CHttpHandler.ashx?id=1199&p=0 Ref. 5.53 - Chiltern District Council, Final Adopted Air Quality Action Plan, 2010. Available at http://www.chiltern.gov.uk/claire/downloads/Final Adopted AQAP Pre Defra.pdf Ref. 5.54 - Three Rivers District Council, Core Strategy, October 2011. Available at http://www.threerivers.gov.uk/Default.aspx/Web/CoreStrategy Ref. 5.55 - Three Rivers District Council, Air Quality Action Plan For Three Rivers District Council, November 2006. Available at http://www.threerivers.gov.uk/Default.aspx/Web/AirPollution Ref. 5.56 - Dacorum Borough Council, Dacorum Borough Local Plan (1991-2011) Written Statement, April 2004. Available at http://www.dacorum.gov.uk/default.aspx?page=1503 Ref. 5.57 - St Albans City and District, City and District of St Albans District Local Plan Review, November 1994. Available at http://www.stalbans.gov.uk/environment-and- planning/planning/policy/currentadoptedlocalplan.aspx Ref. 5.58 - St Albans City and District Council, Air Quality Action Plan for St Albans City and District Council, December 2003. Available at http://www.stalbans.gov.uk/environment-and-planning/pollution/air-pollution/ Ref. 5.59 - Hertsmere Borough Council, Hertsmere Local Plan Through to 2011, May 2003. Available at http://www.hertsmere.gov.uk/planning/ Ref. 5.60 - Hertsmere Borough Council, Air Quality Action Progress Report, 2003. Available at http://www.hertsmere.gov.uk/environmentplanning/pollution/pollutionair.jsp Ref. 5.61 - London Borough of Barnet, Unitary Development Plan 2006. Available at http://www.barnet.gov.uk/downloads/download/572/adopted udp Ref. 5-62 - London Borough of Barnet, Air Quality Action Plan Annual Progress Report, 2008. Available at: http://aqma.defra.gov.uk/action-plans/LBB%20AQAP%202008.pdf Ref. 5.63 - Enfield Council, The Enfield Plan Core Strategy 2010-2025, November 2010. Available at http://www.enfield.gov.uk/info/200057/planning policy Ref. 5.64 - London Borough of Enfield, London Borough of Enfield Air Quality Action Plan, 2003. Available at http://www.enfield.gov.uk/info/413/pollution control-air quality/333/pollution control air quality/2 Ref. 5.65 - Welwyn Hatfield Borough Council, Welwyn Hatfield District Plan Written Statement, 2005. Available at http://www.welhat.gov.uk/index.aspx?articleid=463 Ref. 5.66 - Borough Of Broxbourne, Local Plan Second Review 2001-2011 Written Statement, December 2005. Available at http://www.broxbourne.gov.uk/ Ref. 5.67 - Borough of Broxbourne, Air Quality Action Plan, February 2004. Available at http://www.broxbourne.gov.uk/environment and planning/pollution/pollution control-air quality.aspx
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Ref. 5.68 - Epping Forest District Council, Combined Policies of Epping Forest District Local Plan (1998) and Alterations (2006), February 2008. Available at http://www.eppingforestdc.gov.uk/Council Services/planning/forward planning/default.asp Ref. 5.69 - Brentwood Borough Council, Brentwood Replacement Local Plan, August 2005. Available at http://www.brentwood.gov.uk/index.php?cid=49 Ref. 5.70 - Brentwood Borough Council, Air Quality Action Plan, October 2008. Available at http://www.brentwood.gov.uk/index.php?cid=399 Ref. 5.71 - London Borough of Havering, Core Strategy and Development Control Policies Development Plan Document, 2008. Available at http://www.havering.gov.uk/Pages/Localdevelopmentframework.aspx Ref. 5.72 - Thurrock Council, Thurrock Transport Strategy 2008-2021. Available at http://www.thurrock.gov.uk/travel/transport/pdf/strategy 2008.pdf Ref. 5.73 - Thurrock Council, Local Development Framework, Development Plan Document, December 2011. Available at http://www.thurrock.gov.uk/planning/strategic/pdf/core strategy adopted 20111221 full.pdf Ref. 5.74 - Thurrock Council, Local Air Quality Action Plan, 2004. Available at http://www.thurrock.gov.uk/environment/pollution/pdf/air_quality_plan.pdf Ref. 5.75 - Harlow District Council, Adopted Replacement Harlow Local Plan, July 2006. Available at: http://www.harlow.gov.uk/about_the_council/council_services/environment/planning/forward_planning/curren t_planning_policies/harlow_replacement_local_plan.aspx Ref. 5.76 - Uttlesford District Council, Local Plan 2005. Available at http://www.uttlesford.gov.uk/documents/website/Planning/Local%20Plans%20and%20Local%20Developme nt%20Framework/localplanjan2005.doc Ref. 5.77 – DEFRA: „Projecting NO2 Concentrations‟, April 2012 [Online] Available at http://laqm.defra.gov.uk/documents/BureauVeritas NO2Projections 2766 Final-30 04 2012.pdf Chapter 6 – Cultural Heritage Borough of Broxbourne (2005): Borough of Broxbourne Local Plan Second Review 2001-2011. Adopted on 8 December 2005. Comprising Saved Policies – saved beyond 8th December 2008. British Geological Survey (1993): Epping, Sheet 240, Solid and Geology, 1: 50 000, HMSO British Geological Survey (1993): Hertford, Sheet 239, Solid and Geology, 1: 50 000, HMSO Epping Forest District Council (2008): Combined Policies of Epping Forest District Local Plan (1998) and Alterations (2006). Comprising Saved Policies – saved beyond 9th July 2009 Highways Agency (2007): Cultural Heritage - Design Manual for Roads and Bridges. Volume 11, Section 3, Part 2 Highways Agency (2007): M25 Widening Section 5 (Junction 23 to 27) Environment Assessment Report. Highways Agency (2007): M25 Widening Section 5 (Junction 23 – 27) Addendum Report Institute for Archaeologists (IfA) (2008a): Code of Conduct. Institute for Archaeologists, Reading. Institute for Archaeologists (IfA) (2008b): Standards and Guidance for Desk Based Assessment. Institute for Archaeologists, Reading. Dyson-Bruce, L, Bryant, S and Thompson, I (2006): Historic Landscape Characterisation County Report for Hertfordshire. Government Office for the East of England (2008): East of England Plan The Revision to the Regional Spatial Strategy for the East of England. May 2008. Communities and Local Government. London TSO.
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Highways Agency (2008): Geology and Soils - Design Manual for Roads and Bridges. Volume 11, Section 3 Part 11. Welwyn Hatfield Borough Council (2005): Welwyn Hatfield District Plan Adopted 2005. Comprising Saved Policies – saved beyond 10th April 2008. Welwyn Hatfield Borough Council Chapter 10 – Materials Borough of Broxbourne (2005): Borough of Broxbourne Local Plan Second Review 2001-2011. Adopted on 8 December 2005. Comprising Saved Policies – saved beyond 8th December 2008. Borough of Broxbourne. British Geological Survey: British Geological Survey [Online] Available at: http://www.bgs.ac.uk/geoindex/index.htm CIEH and CL:AIRE (2008): Guidance on Comparing Soil Contamination Data with a Critical Concentration CIRIA (2001): Contaminated Land Risk Assessment: A guide to good practice Contaminated Land: Implementation of Part IIA of the Environmental Protection Act 1990 Part IIA Controlled Waste Regulations 1992 Department for Transport (2009): The Traffic Signs Manual. Chapter 8, Part 1: Design & Part 2: Operations Environment Agency (2005): Environment Agency Guidance on Requirements for Land contamination Reports [Online] Available at: http://www.environment- agency.gov.uk/static/documents/Research/devguidev1 1155225.pdf Epping Forest District Council (2008): Combined Policies of Epping Forest District Local Plan (1998) and Alterations (2006). Published February 2008. Comprising Saved Policies – saved beyond 9th July 2009. Epping Forest District Council. Government Office for the East of England (2008): East of England Plan The Revision to the Regional Spatial Strategy for the East of England. May 2008. Government Office for the East of England. London TSO. Greater London Authority (2004): The London Plan: Spatial Development Strategy for Greater London. Consolidated with Alterations since 2004. February 2008. Hazardous Waste Directive (Council Directive 91/689/EC) Hazardous Waste (England and Wales) Regulations 2005 (SI 2005/894) HMSO (2007): The Construction (Design and Management) Regulations 2007. Statutory Instrument 2007 No. 320.Health and Safety. 6 April 2007 Hertsmere Borough Council (2003): Hertsmere Local Plan Adopted 19th May 2003. Comprising Saved Policies - saved beyond 27th September 2007. Hertsmere Borough Council Highways Agency (2008): Geology and Soils - Design Manual for Roads and Bridges. Volume 11, Section 3, Part 11. London Borough of Enfield (1994): The London Borough of Enfield Unitary Development Plan Adopted 25th March 1994. Comprising Saved Policies - saved beyond 27th September 2007. London Borough of Enfield. MAGIC: Multi Agency Geographic Information for the Countryside [Online] Available at: http://www.magic.gov.uk Site Waste Management Plan (SWMP) Regulations 2008 Waste Management Licensing (England and Wales) (Amendments and Related provisions) (N0. 3) Regulations 2005 Welwyn Hatfield Borough Council (2005): Welwyn Hatfield District Plan Adopted 2005. Comprising Saved Policies – saved beyond 10th April 2008. Welwyn Hatfield Borough Council
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Wildlife and Countryside Act 1981 (Amendment) Regulations 1995 Statutory Instrument 1995 No. 2825 Chapter 11 – Noise Borough of Broxbourne (2005): Borough of Broxbourne Local Plan Second Review 2001-2011. Adopted on 8 December 2005. Comprising Saved Policies – saved beyond 8th December 2008. Borough of Broxbourne. Epping Forest District Council (2008): Combined Policies of Epping Forest District Local Plan (1998) and Alterations (2006). Published February 2008. Comprising Saved Policies – saved beyond 9th July 2009. Epping Forest District Council. Greater London Authority (2004): The London Plan: Spatial Development Strategy for Greater London. Consolidated with Alterations since 2004. February 2008. Hertsmere Borough Council (2003): Hertsmere Local Plan Adopted 19th May 2003. Comprising Saved Policies - saved beyond 27th September 2007. Hertsmere Borough Council. HMSO (1988): Calculation of Road Traffic Noise Highways Agency (2011): Noise and Vibration - Design Manual for Roads and Bridges. Volume 11, Section 3, Part 7 Revision 1 London Borough of Enfield (1994): The London Borough of Enfield Unitary Development Plan Adopted 25th March 1994. Comprising Saved Policies - saved beyond 27th September 2007. London Borough of Enfield. Noise Insulation Regulations (1975) Statutory Instrument No. 1763 Noise Insulation (Amendment) Regulations (1988) Statutory Instrument No. 2000 Welwyn Hatfield Borough Council (2005): Welwyn Hatfield District Plan Adopted 2005. Comprising Saved Policies – saved beyond 10th April 2008. Welwyn Hatfield Borough Council The Environmental Noise (England) Regulations 2006 Statutory Instrument No. 2238. The Environmental Noise (England) (Amendment) Regulations 2008 Statutory Instrument No. 375 The Mayor‟s Ambient Noise Strategy, Mayor of London, 2004 BS5228 Part 1:2009 - Code of practice for noise and vibration control on construction and open site – Part 1: Noise Land Compensation Act 1973 National Planning Policy Framework, DCLG, 2012
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Chapter 12 – Effects on All Travellers Borough of Broxbourne (2005): Borough of Broxbourne Local Plan Second Review 2001-2011. Adopted on 8 December 2005. Comprising Saved Policies – saved beyond 8th December 2008. Borough of Broxbourne. Department for Communities and Local Government (2001): Planning Policy Guidance 13: Transport. Department for Communities and Local Government (DCLG), formerly Office of the Deputy Prime Minister (ODPM). Published March 2001, HMSO. Epping Forest District Council (2008): Combined Policies of Epping Forest District Local Plan (1998) and Alterations (2006). Published February 2008. Comprising Saved Policies – saved beyond 9th July 2009. Epping Forest District Council. Government Office for the East of England (2008): East of England Plan The Revision to the Regional Spatial Strategy for the East of England. May 2008. Government Office for the East of England. London TSO. Greater London Authority (2004): The London Plan: Spatial Development Strategy for Greater London. Consolidated with Alterations since 2004. February 2008. Hertsmere Borough Council (2003): Hertsmere Local Plan Adopted 19th May 2003. Comprising Saved Policies - saved beyond 27th September 2007. Hertsmere Borough Council. Highways Agency (1993): Pedestrians, Equestrians, Cyclists and Community Effects - Design Manual for Roads and Bridges. Volume 11. Section 3, Part 8 Highways Agency (1993): Vehicle Travellers - Design Manual for Roads and Bridges. Volume 11, Section 3, Part 9 London Borough of Enfield (1994): The London Borough of Enfield Unitary Development Plan Adopted 25th March 1994. Comprising Saved Policies - saved beyond 27th September 2007. London Borough of Enfield. Welwyn Hatfield Borough Council (2005): Welwyn Hatfield District Plan Adopted 2005. Comprising Saved Policies – saved beyond 10th April 2008. Welwyn Hatfield Borough Council Chapter 13 – Community and Private Assets Department for Transport (2003): TAG Unit 3.7.2 Land Use Policy Sub-Objective [Online] Available at: http://www.dft.gov.uk/webtag/index.php (accessed 12/10/2009). Department for Transport (2003): TAG Unit 3.7.3 Other Government Policies Sub-Objective [Online] Available at: http://www.dft.gov.uk/webtag/index.php (accessed 12/10/2009). Department for Transport (1998): A New Deal for Transport: Better for Everyone [Online] Available at: http://www.dft.gov.uk/about/strategy/whitepapers/previous/anewdealfortransportbetterfo5695 (accessed 12/10/2009). Department for Transport (2000): Transport 2010: The 10 Year National Plan [Online] Available at: http://www.dft.gov.uk/about/strategy/whitepapers/previous/transporttenyearplan2000 (accessed 12/10/2009). Department for Transport (2000): Tomorrow‟s Roads: Safer for Everyone [Online] Available at: http://www.dft.gov.uk/pgr/roadsafety/strategytargetsperformance/tomorrowsroadssaferforeveryone (accessed 12/10/2009). Department for Transport (2004): The Future of Transport - White Paper CM 6234 [Online] Available at: http://www.dft.gov.uk/about/strategy/whitepapers/previous/fot/ (accessed 12/10/2009). Department for Transport (2007): Towards a Sustainable Transport System - Supporting Economic Growth in a Low Carbon World [Online] Available at: http://www.dft.gov.uk/about/strategy/transportstrategy/hmtlsustaintranssys (access 12/10/2009).
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Department for Transport (2008): Roads – Delivering Choice and Reliability [Online] Available at: http://www.dft.gov.uk/pgr/roads/introtoroads/roadcongestion/roadscommandpaper1.pdf (accessed 12/10/2009). Department for Transport (2009): Britain‟s Transport Infrastructure – Motorways and Major Trunk Roads [Online] Available at: http://www.dft.gov.uk/pgr/roads/network/policy/motorways/ (accessed 2/10/2009). Highways Agency (2008): HA 200/08 Aims and Objectives of Environmental Assessment - Design Manual for Roads and Bridges. Highways Agency (1994): Impact of Road Schemes on Policies and Plans - Design Manual for Roads and Bridges. Volume 11 Section 3 Part 12 Highways Agency: Towards A Balance with Nature Highways Agency Environment Strategic Plan [Online] Available at: http://www.highways.gov.uk/aboutus/672.aspx (accessed 12/10/2009). Highways Agency: Highways Agency Biodiversity Action Plan (HABAP) [Online] Available at: http://www.highways.gov.uk/aboutus/1153.aspx (accessed 12/10/2009). Highways Agency: Highways Agency Strategic Plan for Accessibility [Online] Available at: http://www.highways.gov.uk/aboutus/710.aspx (accessed 12/10/2009). Highways Agency: Working in Partnership: - Highways Agency Strategic Plan for Integration [Online] Available at: http://www.highways.gov.uk/aboutus/2007.aspx (accessed 12/10/2009). Highways Agency: Better Value from Busy Roads: Highways Agency Economic Strategic Plan [Online] Available at: http://www.highways.gov.uk/aboutus/1992.aspx (accessed 12/10/2009). Department for Environment, Farming and Rural Affairs (2000): Our Countryside: The Future – A Fair Deal for Rural England [Online] Available at: http://www.defra.gov.uk/rural/policy/services.htm (accessed 12/10/2009). Department for Environment, Farming and Rural Affairs (2002): Working with the Grain of Nature: A Biodiversity Strategy for England [Online] Available at: http://www.defra.gov.uk/environment/quality/biodiversity/uk/e-biostrat.htm (accessed 12/10/2009). Department for Environment, Farming and Rural Affairs (2007): The Air Quality Strategy for England, Scotland, Wales and Northern Ireland [Online] Available at: http://www.defra.gov.uk/environment/quality/air/airquality/strategy/index.htm (accessed 12/10/2009). Department of Communities and Local Government (2012) National Planning Policy Framework. Government Office for the East of England (2008): The East of England Plan – The Revision to the Regional Spatial Strategy for the East of England [Online] Available at: http://www.gos.gov.uk/goeast/planning/regional planning/ (accessed 12/10/2009). Essex County Council (2006): Essex Local Transport Plan 2006/2011: The Second Essex Local Transport Plan [Online] Available at: http://www.essexcc.gov.uk/vip8/ecc/ECCWebsite/dis/guc.jsp?channelOid=16819&guideOid=39939&guideC ontentOid=44746 (accessed 12/10/2009). Hertfordshire County Council (2006): Hertfordshire Local Transport Plan 2006/07 – 2010/11 [Online] Available at: http://www.hertsdirect.org/envroads/roadstrans/transplan/ltp/ltp2/ltp2march06/ (accessed 12/10/2009) Chapter 14 – Road Drainage and the Water Environment Borough of Broxbourne (2005): Borough of Broxbourne Local Plan Second Review 2001-2011. Adopted on 8 December 2005. Comprising Saved Policies – saved beyond 8th December 2008. Department for Communities and Local Government (2001): Planning Policy Statement 25: Development and Flood Risk. Department for Communities and Local Government (DCLG), formerly Office of the Deputy Prime Minister (ODPM). Published July 2001, HMSO
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Department for Communities and Local Government (2004): Planning Policy Statement 23: Planning and Pollution Control. Department for Communities and Local Government (DCLG), formerly Office of the Deputy Prime Minister (ODPM). Published November 2004, HMSO Environment Agency (no date): River Ecosystem Classication [online]. Available at: http://www.environment- agency.gov.uk/research/planning/40297.aspx Epping Forest District Council (2008): Combined Policies of Epping Forest District Local Plan (1998) and Alterations (2006). Comprising Saved Policies – saved beyond 9th July 2009. Government Office for the East of England (2008): East of England Plan The Revision to the Regional Spatial Strategy for the East of England. May 2008. Communities and Local Government. London TSO. Greater London Authority (2004): The London Plan: Spatial Development Strategy for Greater London: Consolidated with Alterations since 2004. February 2008. Hertsmere Borough Council (2003): Hertsmere Local Plan Adopted 19th May 2003. Comprising Saved Policies - saved beyond 27th September 2007. Highways Agency (2006): Road Drainage and the Water Environment - Design Manual for Roads and Bridges. Volume 11, Section 3, Part 10 Highways Agency (2007): M25 Widening Section 5 (Junction 23 to 27) Environment Assessment Report. Highways Agency (2007): M25 Widening Section 5 (Junction 23 – 27) Addendum Report London Borough of Enfield (1994): The London Borough of Enfield Unitary Development Plan Adopted 25th March 1994. Comprising Saved Policies - saved beyond 27th September 2007. Welwyn Hatfield Borough Council (2005): Welwyn Hatfield District Plan Adopted 2005. Comprising Saved Policies – saved beyond 10th April 2008. Chapter 15 – Assessment of Cumulative Effects Highways Agency (2008): Assessment and Management of Environmental Effects - Design Manual for Roads and Bridges. Volume 11, Section 2, Part 5
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18. Glossary Acoustic Barrier - Solid walls or partitions, solid fences, earth mounds, buildings, etc used to reduce noise, without eliminating it. Active Traffic Management (ATM) - a new motorway Project designed to tackle congestion and improve the reliability of journey times, combining technologies, infrastructure and procedures. The aim of ATM is to make the best use of the existing road space, providing extra capacity for vehicles, whilst minimising environmental disruption. Air Quality Management Area (AQMA) – places where air quality objectives are not likely to be achieved. Where an AQMA is declared, the local authority is obliged to produce an Action Plan in pursuit of the achievement of the air quality objectives. Air Quality Strategy (AQS) Objectives – objectives for key air pollutants to protect health All Lanes Running – the operatic regime for the motorway whereby traffic can use the current hard shoulder as a running lane at all times Ambient Monitoring Stations (AMS) – Locations where the sound pressure level is measured. Ambient Sound - The totally encompassing sound in a given situation at a given time; usually composed of sound from all sources near and far. Amenity – the pleasant or normally satisfactory aspects of a location that contribute to its overall character and the enjoyment of residents or visitors. Annual Average Daily Traffic flows (AADT) – the total volume of vehicle traffic in both directions of a road over the course of a year, divided by 365 days. Appraisal Summary Table (AST) – a one page tabular summary of the main economic, environmental and social impacts of a transport solution. Providing the information in this way enables a clearer and more consistent view to be taken about the value of projects. Appropriate Assessment (AA) - Under Article 6 of the Habitats Directive, an assessment is required where a plan or project may give rise to significant effects upon a site within the Natura 2000 network. If HRA Screening (see definition below) concludes that significant adverse effects are likely then Appropriate Assessment must be undertaken to determine if there will be adverse effects on site integrity. Areas of Archaeological Significance (AAS) – places of special archaeological interest. Average Annual Weekly Traffic (AAWT) Background Noise - Background noise is the term used to describe the noise measured in the absence of the noise under investigation. It is described as the average of the minimum noise levels measured on a sound level meter and is measured statistically as the A-weighted noise level exceeded for ninety percent of a sample period. This is represented as the L90 noise level (see below). Benefit to Cost Ration (BCR) – an indicator used to summarise the overall value for money of the project. Broadband - Containing the full range of frequencies. Built Form – the component features of buildings, streets and spaces that make up the urban environment. Conservation Area – an area given statutory protection under the Planning Acts, in order to preserve and enhance its character and townscape. County Wildlife Sites (CWS) – non-statutory designated areas of land that are important because of their wildlife. Cumulative effects – the summation of impacts that result from changes caused by a development in conjunction with other past, present or reasonably foreseeable actions.
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Decibel (dB) - The level of noise is measured objectively using a Sound Level Meter. This instrument has been specifically developed to mimic the operation of the human ear. The human ear responds to minute pressure variations in the air. These pressure variations can be likened to the ripples on the surface of water but of course cannot be seen. The pressure variations in the air cause the eardrum to vibrate and this is heard as sound in the brain. The stronger the pressure variations, the louder the sound is heard. The range of pressure variations associated with everyday living may span over a range of a million to one. On the top range may be the sound of a jet engine and on the bottom of the range may be the sound of a pin dropping. Instead of expressing pressure in units ranging from a million to one, it is found convenient to condense this range to a scale 0 to 120 and give it the units of decibels. The following are examples of the decibel readings of every day sounds: Four engine jet aircraft at 100m 120dB Riveting of steel plate at 10m 105dB Pneumatic drill at 10m 90dB Circular wood saw at 10m 80dB Heavy road traffic at 10m 75dB Telephone bell at 10m 65dB Male speech, average at 10m 50dB Whisper at 10m 25dB Threshold of hearing, 1000 Hz 0dB dB(A): A-weighted decibels - The ear is not as effective in hearing low frequency sounds as it is hearing high frequency sounds. That is, low frequency sounds of the same dB level are not heard as loud as high frequency sounds. The sound level meter replicates the human response of the ear by using an electronic filter which is called the "A" filter. A sound level measured with this filter switched on is denoted dB(A) or as
LAdB. Practically all noise is measured using the A filter. The sound pressure level in dB(A) gives a close indication of the subjective loudness of the noise. Design Build Finance and Operate (DBFO) Contractor – the contractor responsible for the delivery of the project. Design Manual for Roads and Bridges (DMRB) - is a series of 15 volumes that provide official standards, advice notes and other documents relating to the design, assessment and operation of trunk roads (including motorways). Element – a component part or feature of the landscape (e.g. rivers, trees, hedges, woods). Emergency Refuge Areas (ERA) – designed to be used in all cases of emergency or breakdown, not only when the hard shoulder is being used as a running lane. They are located adjacent to the hard shoulder, are 100 metres long, 4.5 metres deep and occur every 600 - 800 metres. Enhancement – landscape improvement through restoration, reconstruction or creation. Environment – our physical surroundings including air, water and land. Environmental Impact Assessment (EIA) – the evaluation of the impacts on the environment of particular development proposals. Free Field - A situation in which the radiation from a sound source is completely unaffected by the presence of any reflecting surfaces. Green Belt – specially designated area of countryside protected from most forms of development in order to prevent urban sprawl and the coalescence of settlements, preserve the character of existing settlements and encourage development to locate within existing built-up areas.
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Habitat Regulations Assessment Screening (HRA Screening) - the process which initially identifies the likely impacts upon a SAC, SPA or Ramsar site of a project or plan, either alone or in combination with other projects or plans, and considers whether these impacts are likely to be significant. It is important to note that the burden of evidence is to show that there will be no significant effect; if the effect is not known, that would trigger the need for an Appropriate Assessment. Hard Shoulder Running (HSR) – use of the Hard Shoulder as a running lane. Hard Shoulder Running Base (HSR Base) – The option proposed for Section 5. This is the controlled use of the Hard Shoulder during periods of high vehicle flow or incidents, with no environmental enhancement measures designed in. Hard Shoulder Running Plus (HSR Plus) – An alternative option considered for Section 5. This is the controlled use of the Hard Shoulder during periods of high vehicle flow or incidents, with environmental enhancement measures designed in Heritage – historic or cultural associations. Heavy Goods Vehicle (HGV) - HGVs are assumed to be buses, rigid trucks and semi trailer trucks with a weight greater than 3 tonnes. HGVs can be defined in terms of length as buses, or trucks with a length exceeding 5.25 metres. Indirect impacts – impacts on the environment that are not a direct result of the development but are often produced away from it or as a result of a complex association, such as off-site traffic movements. Integrated Demand Management (IDM) - managing the amount of traffic using the motorway by controlling the amount joining and leaving.
Ln noise descriptors - Because noise varies with time, a single noise value cannot adequately define the noise climate. For this reason, the acoustic environment is described using a number of noise level descriptors as follows;
L1 – The sound pressure level that is exceeded for 1% of the time for which the given sound is measured.
L10 – The sound pressure level that is exceeded for 10% of the time for which the given sound is measured.
L10,1-hour – The L10 level measured over a 1 hour period.
LA10,18-hour – The arithmetic average of the A-weighted L10,1-hour levels for the 18 hour period between 6am and 12 midnight on a normal working day. It is a common traffic noise descriptor.
L90 – The level of noise exceeded for 90% of the time. The bottom 10% of the sample is the L90 noise level. The A-weighted L90 is expressed as the LA90.
Leq - Equivalent sound pressure level - the steady sound level that, over a specified period of time, would produce the same energy equivalence as the fluctuating sound level actually occurring.
LAeq,8-hour - The A-weighted Leq noise level for a specific six-hour period – in this case night time (2300 – 0700 hours).
LAmax - The maximum RMS A-weighted sound pressure level occurring within a specified time period. Landscape – soft features of the urban, suburban or rural environment, such as vegetation and green open spaces. Landscape baseline – a description of the environment as it is currently and as it could be expected to develop if the project were not to proceed. Landscape condition – based on judgements about the physical state of a particular landscape/area, and about its visual and functional intactness. It also reflects the state of repair of individual features and elements that make up the character in any one place. Landscape elements – groups of features of the soft landscape, for example roadside planting, street trees, amenity open space.
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Landscape evaluation – the process of attaching value (non-monetary) to a particular landscape area, usually by the application of previously agreed criteria, including consultation and third party documents, in the context of the assessment. Landscape impacts – change in the elements, characteristics, character and qualities of the landscape as a result of development. These impacts can be positive or negative. Landscape feature – prominent eye-catching elements (other than designated ones), for example a church spire, monument or distinctive landmark building, significant mature specimen tree, that contributes to landscape character through appearance or specific civic use. Landscape quality – largely subjective judgement based on particular characteristics that influence the way in which the environment is experienced, including special interests such as cultural associations or heritage interests, the presence and/or type of elements and condition. Landscape regeneration – the re-use or redevelopment of decaying or run-down parts of landscape/areas to bring them new life, vitality, quality and value. Landscape resource – the combination of elements that contribute to landscape context, character and value. Landscape sensitivity – the extent to which a landscape can accept a change of a particular type and scale without unacceptable adverse impacts on its character. Landscape value – areas of formally designated landscape that, through national or local consensus, reflect the value placed by society on particular urban environments or their features. Listed Building – building or other structure of special architectural or historic interest included on a statutory list and assigned a grade (I, II* or II). Loudness - A rise of 10dB in sound level corresponds approximately to a doubling of subjective loudness. That is, a sound of 85dB is twice as loud as a sound of 75dB which is twice as loud as a sound of 65dB and so on. That is, the sound of 85dB is four times the loudness of a sound of 65dB. Magnitude – a combination of the scale, extent and duration of an impact. Methodology – the specific approach and techniques used for a given study. Mitigation – measures, including any process, activity or design to avoid, reduce, remedy or compensate for adverse townscape and visual impacts of a development project. Noise - Sound which a listener does not wish to hear Non- Motorised User (NMU) – Includes cyclists, pedestrians and equestrians. Orbit Multi-Modal Study (Orbit MMS) – was commissioned by the Government Office for the South East and completed in November 2002. The intention of the study was to identify causes of congestion along and approaching the M25, and recommend a preferred strategy of possible solutions to alleviate the impact of congestion on the M25. Perception (of landscape) – the psychology of seeing and possibly attaching a value and/or meaning (to landscape). Public Open Space – land provided in urban or rural areas for public recreation, though not necessarily publicly owned. Public Realm – outdoor areas accessible to the public, providing pedestrian uses and linkages, and with landscape and townscape elements such as street furniture (seating, lighting, signage, etc). Public Right of Way (PRoW) - paths on which the public have a legally protected right to pass. Ramsar Site – wetlands of international importance designated under the Ramsar Convention Receptor – physical landscape resource, special interest or person and/or viewer group that will experience an impact.
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Regionally Important Geological Sites (RIGs) – locally important geological or geomorphological sites (not statutorily protected) Residual impact – an impact that occurs/persists after mitigation measures have been put in place. Scheduled Monument– a nationally important archaeological site or historic building, which has been given protection against unauthorised change. Section 5: Junctions 23 – 27 of M25 Sense of place – the essential character and spirit (genius loci) of an area. Site of Importance for Nature Conservation (SINC) – are sites with wildlife that is of value at a county level (not statutorily protected). Site of Special Scientific Interest (SSSI) – the country's very best wildlife and geological sites, protected by legislation. Sound Level Meter - An instrument consisting of a microphone, amplifier and indicating device, having a declared performance and designed to measure sound pressure levels. Sound Pressure Level - The level of noise, usually expressed in decibels, as measured by a standard sound level meter with a microphone. Sound Power Level - Ten times the logarithm to the base 10 of the ratio of the sound power of the source to the reference sound power. Special Area of Conservation (SAC) - are strictly protected sites designated under the EC Habitats Directive. Special Protection Area (SPA) - are strictly protected sites classified for rare and vulnerable birds, listed in Annex I to the Birds Directive, and for regularly occurring migratory species. Sustainability – meeting the needs of the present without compromising the ability of future generations to meet their own needs (environment, social and economic). Visual amenity – the value of a particular area or view in terms of what is seen. Visual impact – Changes in the appearance of the landscape or in the composition of available views as a result of development, to people‟s responses to these changes, and to the overall impacts in regard to visual amenity. This can be positive (i.e. beneficial or an improvement) or negative (i.e. adverse or a detraction). Visual envelope – extent of potential visibility to or from a specific area or feature. Widening Base - An alternative considered for Section 5. Widening the carriageway to provide an additional lane (not using the hard shoulder), without environmental enhancement measures designed in Widening Plus - An alternative considered for Section 5. Widening the carriageway to provide an additional lane (not using the hard shoulder), with environmental enhancement measures designed in Zone of Visual Influence (ZVI) – area within which a proposed development may have an influence or impact.
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